All Exams  >   Grade 9  >   Biology for Grade 9  >   All Questions

All questions of Characteristics and Classification of Living Organisms for Grade 9 Exam

Which is the major component of the living environment?
  • a)
    Water
  • b)
    trees
  • c)
    all of these
  • d)
    sun
Correct answer is option 'C'. Can you explain this answer?

Pragati Das answered
3. All of these
Explanation: The living environment is made up of various essential components such as water, trees, and the sun, all of which are crucial for life. Water is vital for hydration and biological processes, trees provide oxygen and habitats, and the sun is the primary source of energy for all living organisms through processes like photosynthesis. Therefore, all of these components play a major role in the living environment.

Which of the following is not the characteristic of a living thing?
  • a)
    Growth
  • b)
    Respiration
  • c)
    Decay
  • d)
    None of these
Correct answer is option 'C'. Can you explain this answer?

Dr Manju Sen answered
Decay is the process in which the dead remains of a living organism gets decayed in the presence of bacterias and fungus. It can only take place after the death of an organism. It cannot be considered as a characteristic feature of living beings because this process can take place only if a living being is dead.

Which is not an abiotic component of environment?
  • a)
    Organism
  • b)
    Soil
  • c)
    Water
  • d)
    Air
Correct answer is option 'A'. Can you explain this answer?

Kayra answered
The organism is not an obiotic component of the ecosystem. it includes plants ,animals ,and humans resources that are not living are abiotic resources this resources fall under the border category of natural resources that exist naturally in the world and are not man made are man made so the answer is option number a if you like man so please UP vote it please please

Primary function of scales on fishes is to
  • a)
    help them to swim
  • b)
    keep them warm
  • c)
    protect themselves
  • d)
    attract other fishes
Correct answer is option 'C'. Can you explain this answer?

Gunjan Lakhani answered
Fish scales provide a protective layer that shields the fish from injuries, parasites, and infections. They also help in reducing friction as the fish moves through the water, but their main role is protection.

Organisms that obtain their food from others are called
  • a)
    Producers
  • b)
    Scavengers
  • c)
    Autotrophs
  • d)
    Heterotrophs
Correct answer is option 'D'. Can you explain this answer?

Coachify answered
Organisms that obtain their food from others are called Heterotrophs. Heterotrophs are organisms that cannot produce their own food and must rely on other organisms as a source of energy and nutrients. This includes animals, fungi, and some bacteria that feed on other organisms or organic matter. In contrast, autotrophs are organisms that can produce their own food, such as plants and algae, through photosynthesis or chemosynthesis.

Which is an aquatic adaptation?
  • a)
    Light and hollow bones
  • b)
    Hair on body
  • c)
    Streamlined body and Gills
  • d)
    None of these
Correct answer is option 'C'. Can you explain this answer?

Neha Mehta answered
Streamlined body is an aquatic adaptation.

A streamlined body is a characteristic that allows an organism to move through water with minimal resistance. This adaptation is particularly important for aquatic animals as they need to be able to move efficiently and quickly in their aquatic environment.

Here is a detailed explanation of why a streamlined body is an aquatic adaptation:

1. Definition of a streamlined body:
A streamlined body refers to a shape that is designed to reduce drag or resistance when an organism moves through a fluid medium, such as water. It is typically elongated and tapered at both ends, resembling a teardrop shape.

2. Benefits of a streamlined body:
Having a streamlined body provides several advantages to aquatic organisms:

- Reduced drag: The streamlined shape minimizes the resistance of water against the organism's body, allowing it to move through water more easily and efficiently.
- Increased speed: By reducing drag, a streamlined body enables aquatic organisms to swim faster and more effortlessly.
- Energy conservation: With less drag, organisms can conserve energy while swimming, as they don't need to exert as much force to overcome resistance.

3. Examples of aquatic organisms with a streamlined body:
Numerous aquatic animals possess a streamlined body shape as an adaptation to their aquatic lifestyle. Some examples include:

- Fish: Fish are known for their torpedo-shaped bodies, which allow them to move swiftly through water.
- Dolphins: These marine mammals have sleek bodies that enable them to swim at high speeds.
- Sharks: Sharks have a streamlined body shape that assists them in swimming efficiently and hunting prey effectively.
- Whales: Whales also have a streamlined body, allowing them to travel long distances in the water with minimal effort.

In conclusion, a streamlined body is an aquatic adaptation that provides aquatic organisms with reduced drag, increased speed, and energy conservation. This adaptation is essential for their survival and ability to navigate through their watery habitats efficiently.

What term describes the method by which organisms adjust to their surroundings over a short period of time?
  • a)
    Acclimatisation
  • b)
    Transformation
  • c)
    Evolution
  • d)
    Revolution
Correct answer is option 'A'. Can you explain this answer?

Rohini Seth answered
 
Acclimatisation is when organisms make small changes in their bodies over a short time to adapt to changes in their environment. For example, when we go to a new place, our body adjusts slowly to the different conditions there. This process helps living things survive in different places.
 
Topic in NCERT: Acclimatisation
Line in NCERT: "Such small changes that take place in the body of a single organism over short periods, to overcome small problems due to changes in the surroundings, are called acclimatisation."

Fishes move about in the water with the help of their
  • a)
    mouths and gills
  • b)
    legs and scale
  • c)
    fins and tails
  • d)
    wings and tails
Correct answer is option 'C'. Can you explain this answer?

Lekshmi Sen answered

How Fishes Move in Water

Fishes are able to move in water efficiently due to their unique anatomical features. One of the key features that help fishes move around in water is their fins and tails.

Fins

Fishes have various types of fins that play different roles in their movement.
- Dorsal fins help fishes to keep their balance and prevent rolling.
- Pectoral fins are used for steering and stopping.
- Pelvic fins help fishes to control their depth in the water.
- Anal fins assist in stabilizing the fish's body.

Tails

The tail of a fish, also known as the caudal fin, is the main propeller for their movement.
- The tail moves from side to side, creating thrust and propelling the fish forward.
- The shape of the tail varies among different species of fish, affecting their swimming speed and agility.

Combined Movement

By using their fins for steering and stabilizing and their tails for propulsion, fishes are able to navigate through the water with precision.
- The coordination between the fins and tail allows fishes to swim in various directions, change their speed, and escape predators.

In conclusion, the fins and tails of fishes work together to provide them with the necessary agility and speed to move effectively in water. These adaptations have evolved over time to help fishes survive in their aquatic environment.

How does a chameleon protect itself from its enemies?
  • a)
    By changing the colour of its body.
  • b)
    By releasing bad small.
  • c)
    It has a hard shell on its body.
  • d)
    By curling its body.
Correct answer is option 'A'. Can you explain this answer?

Ananya Mishra answered
Animals have their own special characteristics to protect themselves from enemies and from danger. Chameleon protect itself from enemies by changing the colour of the body.

In which habitat, animals with thick fur are most likely to be found?
  • a)
    Grassland
  • b)
    Mountain
  • c)
    Desert
  • d)
    Ocean
Correct answer is option 'B'. Can you explain this answer?

Devika Nair answered
Mountains usually have trees that cools the environment. Hence, the animals with thick fur are most likely to be found in mountains, fur insulate the body and keeps the body warm.

Which of the following is a biotic component of a habitat?
  • a)
    Water
  • b)
    Plants
  • c)
    Soil 
  • d)
    Air
Correct answer is option 'B'. Can you explain this answer?

Vp Classes answered
The correct answer is B: Plants. Plants are biotic components of habitat because they are living organisms. Biotic components include all living things such as animals, bacteria, fungi, and plants.

Which pair has not been correctly paired?
  • a)
    Camel - Desert
  • b)
    Germs - Air
  • c)
    Polar bear - Snow
  • d)
    Whale - River
Correct answer is option 'D'. Can you explain this answer?

Pragati Khanna answered
  1. Camel - Desert: Camels are well adapted to live in desert environments. They can survive with little water and have thick fur that helps insulate them from the heat.
  2. Germs - Air: Germs, or microorganisms, can be found in the air, especially in dust and aerosols. They can spread diseases through the air, making this pairing correct.
  3. Polar bear - Snow: Polar bears are native to Arctic regions, where there is a lot of snow and ice. They are excellent swimmers and primarily hunt seals on the sea ice, making this pairing accurate.
  4. Whale - River: This pairing is incorrect because whales are marine animals that live in oceans. While some smaller species, like dolphins, can enter rivers, true whales do not typically inhabit freshwater rivers.
In summary, the pair "Whale - River" does not represent a correct association since whales are found in saltwater environments, not in rivers.

Which one of the following is not terrestrial habitat?
  • a)
    Ocean
  • b)
    Soil
  • c)
    Tree
  • d)
    Desert
Correct answer is option 'A'. Can you explain this answer?

Puja Sharma answered
Ocean is the answer because terrestrial habitat are the habitat which in related to forest,land,animals and ocean and land are different and both has different properties so all the option are related to land,forest and more except ocean

Which of the following is an abiotic component of habitat?
  • a)
    Tulsi
  • b)
    Snail
  • c)
    Bacteria
  • d)
    Water
Correct answer is option 'D'. Can you explain this answer?

Arjun Ghosh answered
Abiotic components of a habitat are non-living factors that influence the living organisms within an ecosystem. These components include factors such as temperature, sunlight, water, soil, and air. Among the given options, water is the only abiotic component.

Water as an abiotic component of habitat:
- Water is essential for the survival of all living organisms. It serves as a medium for many biological processes and is necessary for the functioning of cells and tissues.
- It provides a habitat for various aquatic organisms such as fish, amphibians, and aquatic plants.
- Water availability and quality influence the distribution and abundance of organisms in an ecosystem. Different species have different requirements for water, and its availability can determine the presence or absence of certain species.
- Water plays a crucial role in regulating temperature within an ecosystem. It has a high specific heat capacity, which means it can absorb and release heat without significant temperature changes. This helps maintain stable temperatures in both aquatic and terrestrial habitats.
- Water also acts as a solvent, allowing many substances to dissolve and be transported within an organism's body or throughout the environment. It facilitates the movement of nutrients and minerals in the soil, which are essential for plant growth.
- Additionally, water contributes to the physical structure of habitats. It shapes the landscape through erosion and deposition, creating various landforms such as rivers, lakes, and valleys.

In contrast, the other options given - Tulsi, Snail, and Bacteria - are all living organisms and thus biotic components of a habitat. Tulsi is a plant, snail is an animal, and bacteria are microorganisms. Biotic components interact with abiotic components to form complex ecosystems.

The plants undergo excretion by
  • a)
    Storing the wastes
  • b)
    Secretions
  • c)
    Urine formation
  • d)
    Both A and B
Correct answer is option 'D'. Can you explain this answer?

Praveen Kumar answered
Plants do not excrete waste in the same way animals do, but they do have mechanisms to deal with waste products:
  • A: Storing the wastes: Plants can store waste products like resins, tannins, or certain other compounds in vacuoles, where they are kept in a non-toxic form.
  • B: Secretions: Some plants excrete waste through their leaves in the form of secretions such as oils, resins, or other substances. For example, some plants excrete excess salts through their leaves.
Plants do not produce urine (as in the case of animals), so C is not the correct answer.
Hence, D: Both A and B is the correct answer.

Yaks have one of the following on their bodies to keep them warm. This one is
  • a)
    hair
  • b)
    feathers
  • c)
    scales
  • d)
    shells
Correct answer is option 'A'. Can you explain this answer?

Yaks have hair to keep them warm.
Explanation:
- Yaks are a species of large, long-haired mammals that are native to the Himalayan region of Asia.
- Hair is an important adaptation that helps yaks survive in their cold and harsh environments.
- The hair on a yak's body provides insulation, helping to retain body heat and keep them warm.
- Yaks have a thick double coat of hair consisting of a coarse outer layer and a soft inner layer.
- The outer layer of hair helps to protect the yak from the elements, such as snow, wind, and rain.
- The inner layer of hair acts as an insulating layer, trapping warm air close to the yak's body.
- The combination of these two layers of hair helps to keep the yak warm in extremely cold temperatures.
- Yaks also have longer hair around their necks and shoulders, forming a "mane" that provides additional insulation and protection.
- This hair also helps to keep the yak's skin dry by repelling moisture.
- Yaks have evolved to have hair as their primary defense against the cold, unlike other animals that may have feathers, scales, or shells.

Which is of the following is not exclusive only to living organisms?
  • a)
    Growth in size
  • b)
    Respiration
  • c)
    Reproduction
  • d)
    Excretion
Correct answer is option 'A'. Can you explain this answer?

Edgy Education answered
  • A: Growth in size: Growth is not exclusive to living organisms. Non-living things can also grow in size through processes like accumulation of material (e.g., crystals growing larger or mountains forming).
  • B: Respiration: This is exclusive to living organisms. It refers to the process of taking in oxygen and releasing carbon dioxide to produce energy.
  • C: Reproduction: This is exclusive to living organisms. Reproduction is the process by which organisms produce offspring.
  • D: Excretion: This is exclusive to living organisms. Excretion refers to the removal of waste products from the body.
Therefore, the correct answer is A: Growth in size, as it is not exclusive to living organisms.

Which statements are true about the tree in hilly areas?
  • a)
    These trees are normally cone shaped.
  • b)
    They have sloping branches.
  • c)
    The leaves of some of these trees are needle-like.
  • d)
    All of the above.
Correct answer is option 'D'. Can you explain this answer?

Rutuja Roy answered
Introduction:
The tree in hilly areas is a unique ecosystem that adapts to the specific conditions of hilly terrain. These trees have certain characteristics that help them thrive in these environments. This response will discuss the statements given in the question and explain why each statement is true.

Explanation:

Statement a) These trees are normally cone shaped:
- One of the characteristics of trees in hilly areas is their cone-shaped structure. This shape helps the trees withstand strong winds that are often present in hilly regions.
- The cone-shaped structure of these trees allows wind to pass through them easily, reducing the risk of branches breaking or the entire tree toppling over.
- Additionally, the cone shape helps the tree shed snow more easily, preventing excess weight on the branches that could cause them to snap.

Statement b) They have sloping branches:
- Sloping branches are another adaptation of trees in hilly areas.
- Sloping branches help the tree withstand heavy snowfall. When snow accumulates on the branches, the sloping shape allows the snow to slide off more easily, preventing the branches from breaking under the weight.
- This adaptation is essential for the survival of these trees in regions with frequent snowfall.

Statement c) The leaves of some of these trees are needle-like:
- Many trees in hilly areas have needle-like leaves.
- Needle-like leaves have several advantages in hilly environments. They often have a waxy coating that helps reduce water loss through evaporation, allowing the tree to conserve water in dry and windy conditions.
- The needle-like leaves also minimize the surface area exposed to the wind, reducing the risk of excessive moisture loss.
- Furthermore, needle-like leaves are better adapted for shedding snow, as the narrow shape prevents snow from accumulating and weighing down the branches.

Conclusion:
In conclusion, all the statements given in the question are true. The tree in hilly areas is cone-shaped, has sloping branches, and some of these trees have needle-like leaves. These characteristics are adaptations that help the trees survive in the challenging conditions of hilly regions, including strong winds, heavy snowfall, and dry environments.

Animals and plants have certain features which make them to survive in a particular habitat. This is called
  • a)
    speciation
  • b)
    adaptation
  • c)
    specialisation
  • d)
    evolution
Correct answer is option 'B'. Can you explain this answer?

Adaptation

Definition: Adaptation refers to the process by which animals and plants develop certain features or traits that allow them to survive and thrive in their specific environment or habitat. These adaptations can be physical, behavioral, or physiological in nature.

Physical Adaptations:
- Animals and plants may have specific physical features that help them survive in their habitat. For example, the long neck of a giraffe allows it to reach leaves high up in trees.
- Some animals have camouflage, which helps them blend into their surroundings and avoid predators. This is seen in animals like chameleons and certain insects.
- Plants may have thorns or spines that deter animals from eating them, protecting them from herbivores.

Behavioral Adaptations:
- Animals may develop certain behaviors that increase their chances of survival. For instance, birds migrate to warmer regions during the winter to find food and escape harsh conditions.
- Some animals hibernate during the winter months, reducing their metabolic rate and conserving energy until food becomes more available.
- Plants may have specific flowering and fruiting periods to attract pollinators or dispersers.

Physiological Adaptations:
- Animals and plants may have internal physiological adaptations that help them survive in their habitat. For example, desert animals have the ability to store and conserve water efficiently.
- Some plants have developed mechanisms to tolerate extreme temperatures or high levels of salinity in their environment.

Importance of Adaptation:
- Adaptations are crucial for the survival and reproductive success of animals and plants. They allow organisms to better compete for resources and avoid predation.
- Without adaptations, organisms would be less suited to their environment and would struggle to survive and reproduce.
- Adaptations can also evolve over time through the process of natural selection, where individuals with beneficial traits are more likely to pass them on to future generations.

In conclusion, adaptation refers to the various features and traits that animals and plants develop to survive in their specific habitat. These adaptations can be physical, behavioral, or physiological in nature and are essential for the survival and reproductive success of organisms.

What adaptation allows desert animals to conserve water effectively?
  • a)
    Thick fur
  • b)
    Large ears
  • c)
    Nocturnal behavior
  • d)
    Bright coloration
Correct answer is option 'C'. Can you explain this answer?

Nocturnal behavior is an adaptation that allows desert animals to conserve water effectively. By being active during the cooler nighttime hours, these animals reduce their water loss through evaporation compared to daytime activity when temperatures are higher. This adaptation helps them avoid the extreme heat of the desert and conserve vital moisture.

Which of these adaptations is not shown by a camel for living in deserts?
  • a)
    Perspires a lot
  • b)
    Passes scanty of urine
  • c)
    Has a hump on its back.
  • d)
    The sole of feet have sort of pads.
Correct answer is option 'A'. Can you explain this answer?

Anisha Iyer answered
Understanding Camel Adaptations
Camels are remarkable animals specially adapted to thrive in the harsh conditions of desert environments. Here’s a breakdown of their adaptations:
1. Limited Perspiration
- Camels are known for their ability to conserve water.
- They do not perspire a lot, which helps them retain body fluids.
- In fact, a camel can lose up to 25% of its body weight due to sweating without suffering from dehydration.
2. Scanty Urine Production
- Camels produce very little urine, which reduces water loss.
- Their urine is highly concentrated, further conserving water.
- This adaptation is crucial for survival in arid habitats where water is scarce.
3. The Hump
- The hump on a camel’s back is a fat storage area.
- This fat can be metabolized into water and energy when food is scarce.
- It also helps regulate body temperature, allowing camels to withstand extreme heat.
4. Specialized Feet
- Camels have large, padded feet that prevent them from sinking into the sand.
- The pads provide stability and support while walking on hot desert surfaces.
- This adaptation allows them to traverse vast distances in search of food and water.
Conclusion
In conclusion, the statement that camels "perspire a lot" is incorrect. Instead, they possess various adaptations, such as limited perspiration, the ability to produce scanty urine, a hump for fat storage, and specialized feet, all of which enable them to survive in the desert environment.

Respiration in aquatic animals occurs by
  • a)
    lungs
  • b)
    gills
  • c)
    nostrils
  • d)
    legs
Correct answer is option 'B'. Can you explain this answer?

Dishani Pillai answered
Understanding Aquatic Respiration
Aquatic animals, such as fish, amphibians, and some invertebrates, primarily use gills for respiration. This specialized organ allows them to extract oxygen from water, which is essential for their survival.
How Gills Work
- Gills are feathery structures located on the sides of the head or body of aquatic animals.
- They contain thin membranes that are rich in blood vessels, creating a large surface area for gas exchange.
- When water passes over the gills, oxygen diffuses from the water into the blood, while carbon dioxide diffuses from the blood into the water.
Why Gills are Essential
- Aquatic environments have lower oxygen concentrations compared to air, making the efficiency of gills crucial.
- Gills enable continuous oxygen absorption even when the animal is stationary, as water flows over them.
Comparison with Other Respiratory Organs
- Lungs: Used by terrestrial animals (like mammals) to breathe air; not effective in water.
- Nostrils: Primarily for air-breathing animals; not applicable for most aquatic animals.
- Legs: Some amphibians may use their skin for respiration, but this is not their primary method.
Conclusion
In summary, gills are the primary respiratory organs for aquatic animals, allowing them to thrive in water environments by efficiently extracting oxygen necessary for their metabolic processes. Understanding this helps us appreciate the adaptations these animals have developed to survive in their habitats.

Which organism depends on abiotic components for food?
  • a)
    Insects
  • b)
    Birds
  • c)
    Plants
  • d)
    Fish
Correct answer is option 'C'. Can you explain this answer?

Plants depend on abiotic components for food. They use carbon dioxide, water and sunlight for preparing food by photo-synthesis.

What is the primary function of the cactus's spines in its adaptation to the desert environment?
  • a)
    To store water
  • b)
    To reduce water loss
  • c)
    To protect against herbivores
  • d)
    To perform photosynthesis
Correct answer is option 'B'. Can you explain this answer?

EduRev Class 6 answered
The primary function of the cactus's spines is to reduce water loss. In the desert environment, where water is scarce, cactus plants have adapted by modifying their leaves into spines. This adaptation minimizes the surface area from which water can evaporate, helping the plant conserve moisture. The cactus's thick, waxy stem and deep roots also contribute to its ability to survive in arid conditions.

Organisms can breathe through
  • a)
    Nostrils
  • b)
    Skin
  • c)
    Gills
  • d)
    All of the above
Correct answer is option 'D'. Can you explain this answer?

Praveen Kumar answered
Organisms can breathe through different parts of their body depending on their species:
  • A: Nostrils: Many land animals, including humans, breathe through their nostrils. The air is drawn into the lungs through the nose.
  • B: Skin: Some organisms, like amphibians (e.g., frogs) and certain worms, can absorb oxygen through their skin, especially when they are in moist environments.
  • C: Gills: Aquatic animals, such as fish, breathe through gills. Gills extract oxygen from water.
So, the correct answer is D: All of the above, as different organisms can use nostrils, skin, or gills for respiration.

Which of the following is represented by "X" in the figure given below? 
 
  • a)
    Ocean
  • b)
    Island
  • c)
    Grassland
  • d)
    Snow land
Correct answer is option 'C'. Can you explain this answer?

Terrestrial ecosystem includes those organisms which live on land. It is classified into three types ? Forest ecosystem. Grassland ecosystem and Desert ecosystem.

Sunlight, water and air are
  • a)
    abiotic components
  • b)
    habitats
  • c)
    biotic components
  • d)
    adaptations
Correct answer is option 'A'. Can you explain this answer?

Sankar Saha answered
Sunlight, water, and air are abiotic components.

Explanation:
Sunlight, water, and air are essential factors for the survival of living organisms. They are considered abiotic components because they are non-living elements that affect the living organisms in an ecosystem. Let's discuss each of these components in detail:

1. Sunlight:
- Sunlight is a form of energy that comes from the sun.
- It provides the primary source of energy for almost all life on Earth through the process of photosynthesis.
- Plants and other autotrophic organisms use sunlight to convert carbon dioxide and water into glucose and oxygen.
- This glucose is then utilized by plants as a source of energy to carry out various life processes.
- Sunlight also plays a crucial role in maintaining temperature, seasonal changes, and the water cycle.

2. Water:
- Water is another essential abiotic component for life.
- It is required by all living organisms for various physiological processes.
- Water is a universal solvent and is involved in various chemical reactions within cells.
- It helps in the transportation of nutrients and waste products within organisms.
- Water also plays a vital role in regulating body temperature and maintaining the moisture content of organisms.

3. Air:
- Air is the mixture of gases present in the Earth's atmosphere.
- It consists mainly of nitrogen, oxygen, carbon dioxide, and traces of other gases.
- Oxygen is crucial for the process of respiration, which provides energy to living organisms.
- Carbon dioxide is essential for photosynthesis in plants.
- Air also carries other substances such as pollen, spores, and pollutants that can affect the health of organisms.

In conclusion, sunlight, water, and air are abiotic components because they are non-living elements that are vital for the survival of living organisms. They provide energy, nutrients, and other essential factors necessary for the functioning of ecosystems.

Which is of the following is not a characteristic feature of aquatic plants
  • a)
    Short roots
  • b)
    Long slender stems
  • c)
    Ribbon shaped leaves
  • d)
    Long deep roots
Correct answer is option 'D'. Can you explain this answer?

EduRev Class 6 answered
  • A: Short roots: Aquatic plants typically have short roots because they don’t need to anchor deeply in the soil. The water provides buoyancy, and the roots mainly serve to absorb nutrients.
  • B: Long slender stems: Aquatic plants often have long, slender stems that help them float or sway with the water currents.
  • C: Ribbon-shaped leaves: Many aquatic plants have ribbon-shaped or elongated leaves to reduce resistance to water currents and to efficiently absorb sunlight.
  • D: Long deep roots: Aquatic plants generally do not have long, deep roots like terrestrial plants. Their roots are mostly short, as they do not need to anchor deeply into the ground but rather float or remain in shallow water.
Therefore, the correct answer is D: Long deep roots, as it is not characteristic of most aquatic plants.

Which of the following animals does not have gills?
  • a)
    Squids
  • b)
    shark
  • c)
    Dolphin
  • d)
    Fish
Correct answer is option 'C'. Can you explain this answer?

Charvi Pillai answered
Explanation:

Introduction:
Gills are specialized organs that aquatic animals use to extract oxygen from water. They are found in a variety of aquatic animals, but not all animals that live in water have gills.

Dolphin:
Dolphins are mammals and do not have gills. They are warm-blooded animals that breathe air, just like humans. Dolphins have lungs, which they use to take in oxygen from the air. When a dolphin swims to the surface of the water, it exhales through its blowhole and inhales fresh air. This allows them to survive in aquatic environments while still needing to breathe air.

Squids and Octopus:
Both squids and octopuses are cephalopods, which are a type of mollusk. They do have gills and use them to extract oxygen from water. These animals have a specialized structure called a gill lamella, which helps them efficiently extract oxygen from water. Squids and octopuses are able to pump water over their gills and extract the oxygen needed for respiration.

Fish:
Fish are the most common animals with gills. They have gill arches that support their gill filaments, where gas exchange takes place. Water flows over the gill filaments, and oxygen is extracted from the water while carbon dioxide is released. Fish are able to extract oxygen from water due to their gills, which allows them to live and survive in aquatic environments.

Conclusion:
In conclusion, out of the given options, the animal that does not have gills is the dolphin. Dolphins are mammals and have lungs to breathe air, unlike squids, octopuses, and fish that have gills for extracting oxygen from water.

What is the primary reason animals in grasslands need to be fast?
  • a)
    To find food
  • b)
    To escape from predators
  • c)
    To build nests
  • d)
    To attract mates
Correct answer is option 'B'. Can you explain this answer?

In grasslands, animals need to be fast primarily to escape from predators. With few trees or places to hide, speed becomes a crucial adaptation for survival. Fast-running animals can evade predators more effectively, increasing their chances of survival in an open and exposed habitat.

The plant in the given figure responds to 
 
  • a)
    touch
  • b)
    sunlight
  • c)
    gravity
  • d)
    water
Correct answer is option 'B'. Can you explain this answer?

Pragati Khanna answered
Basic needs required for a plant to grow are air, water and sunlight. It prepares its food in the presence of sunlight. Its shoot system or stem respond to light and bends towards the direction of sunlight.

Which of the following is NOT an abiotic factor of a habitat?
  • a)
    Water
  • b)
    Soil
  • c)
    Air
  • d)
    Animals
Correct answer is option 'D'. Can you explain this answer?

Dr Manju Sen answered
Animals are not abiotic factors; they are biotic factors. Abiotic factors include non-living components of the environment, such as water, soil, and air, which affect the living organisms within a habitat. Biotic factors, on the other hand, include all the living organisms in an ecosystem.

The removal of waste substances from the body is called
  • a)
    reproduction
  • b)
    respiration
  • c)
    breathing
  • d)
    excretion
Correct answer is option 'D'. Can you explain this answer?

Anirban Saini answered
The removal of waste substances from the body is called excretion.

Excretion is the process by which waste substances, produced as a result of various metabolic activities, are removed from the body. These waste substances can be harmful if they accumulate in the body, so excretion is necessary to maintain a healthy internal environment.

Importance of excretion:
Excretion plays a vital role in maintaining homeostasis, which is the body's ability to regulate and maintain a stable internal environment. It helps in the removal of harmful metabolic waste products, toxins, and excess substances from the body. Some of the key waste substances that are eliminated through excretion include:

1. Carbon dioxide: During cellular respiration, carbon dioxide is produced as a waste product. It is transported through the bloodstream to the lungs, where it is eliminated by exhalation.

2. Nitrogenous wastes: These are produced by the breakdown of proteins and nucleic acids. The main nitrogenous waste in humans is urea, which is formed in the liver and excreted by the kidneys in the form of urine.

3. Excess water and salts: The kidneys play a crucial role in maintaining the balance of water and electrolytes in the body. They filter the blood, reabsorb necessary substances, and excrete excess water and salts through urine.

Organs involved in excretion:
Several organs are involved in the excretory process, each performing specific functions:

1. Skin: The skin helps in the excretion of sweat, which contains water, salts, and small amounts of urea. Sweating helps regulate body temperature and eliminates certain waste products.

2. Lungs: Carbon dioxide, a waste product of cellular respiration, is eliminated through exhalation. The respiratory system plays a crucial role in gas exchange, ensuring the removal of carbon dioxide and the intake of oxygen.

3. Liver: The liver is responsible for the breakdown of toxins and the synthesis of urea. It detoxifies harmful substances and converts them into less toxic forms that can be eliminated from the body.

4. Kidneys: The kidneys are the primary excretory organs in the body. They filter waste products, excess water, and salts from the blood to produce urine. The urine is then transported to the bladder for storage and eventually eliminated from the body through the urethra.

Conclusion:
Excretion is a vital process for maintaining a healthy internal environment. It involves the removal of waste substances from the body, which are produced as a result of various metabolic activities. The organs involved in excretion, such as the skin, lungs, liver, and kidneys, play specific roles in eliminating waste products and maintaining homeostasis.

Which of the following habitats is described as "terrestrial"?
  • a)
    Coral reefs
  • b)
    Forests
  • c)
    Lakes
  • d)
    Oceans
Correct answer is option 'B'. Can you explain this answer?

Dr Manju Sen answered
Forests are an example of terrestrial habitats. Terrestrial habitats are environments found on land, as opposed to aquatic habitats, which are found in water. Examples of terrestrial habitats include forests, grasslands, and deserts, where various plants and animals have adapted to live and thrive.

Cactus plant lives in the terrestrial region of
  • a)
    grasslands
  • b)
    forests
  • c)
    mountains
  • d)
    deserts
Correct answer is option 'D'. Can you explain this answer?

Sounak Ghoshal answered
Introduction:
Cactus plants are well-known for their ability to survive in harsh and arid environments. They have adapted to live in regions with very little water and high temperatures. As a result, cactus plants are commonly found in deserts around the world.

Desert Environment:
Deserts are characterized by extremely dry conditions, receiving very little rainfall throughout the year. The lack of water makes it difficult for most plants to survive in these regions. However, cactus plants have evolved to thrive in such environments.

Adaptations of Cactus Plants:
Cactus plants have several adaptations that enable them to survive in deserts:

1. Succulent Stem: Cacti store water in their thick and fleshy stems. This allows them to retain water for long periods and withstand drought conditions.

2. Reduced Leaves: Cactus plants have modified their leaves into spines or scales to minimize water loss through transpiration. This adaptation helps them conserve water and reduce the risk of dehydration.

3. Shallow and Widespread Root System: Cacti have shallow roots that spread out horizontally near the surface of the soil. This allows them to quickly absorb any available water, even from light rainfall or morning dew.

4. Waxy Outer Layer: The outer layer of cactus plants is covered with a thick, waxy substance called cuticle. This cuticle helps to prevent water loss through evaporation.

5. Camouflage: Some cacti have a greenish-gray coloration that helps them blend in with the surrounding desert environment. This camouflage helps protect them from predators and reduces the amount of sunlight they absorb, minimizing water loss.

Conclusion:
In conclusion, cactus plants are primarily found in deserts due to their remarkable adaptations to survive in arid conditions. Their succulent stems, reduced leaves, shallow root systems, waxy outer layer, and camouflage allow them to thrive in regions with little water and high temperatures. Therefore, the correct answer to the question is option 'D' - deserts.

Chapter doubts & questions for Characteristics and Classification of Living Organisms - Biology for Grade 9 2025 is part of Grade 9 exam preparation. The chapters have been prepared according to the Grade 9 exam syllabus. The Chapter doubts & questions, notes, tests & MCQs are made for Grade 9 2025 Exam. Find important definitions, questions, notes, meanings, examples, exercises, MCQs and online tests here.

Chapter doubts & questions of Characteristics and Classification of Living Organisms - Biology for Grade 9 in English & Hindi are available as part of Grade 9 exam. Download more important topics, notes, lectures and mock test series for Grade 9 Exam by signing up for free.

Biology for Grade 9

50 videos|96 docs|27 tests

Top Courses Grade 9