Class 7 Science Chapter 1 Practice Question Answers - Nutrition in Plants

Q1: The plant which traps and feeds on insects is:
(a) Cuscuta
(b) China rosa
(c) Pitcher plant
(d) Rose
Ans: (a)
Pitcher plant is the plant which traps and feeds on insects.

Solution: 

The correct option is C.

Explanation of the correct option:

• The plant which catches insects and feeds on them is the pitcher plant.
• The numerous carnivorous plants in the pitcher plant family have modified stems named pitfall traps.
• Insectivorous plants trap nutrient-rich insects because they grow in shallow soil which is nutrient deficient.

Explanation of the incorrect options:

Option A:

• Cuscuta is a parasitic plant.
• The stems of Cuscuta grow into the host body and extract nutrients and water.

Option B:

• China rose plant is an autotrophic plant.
• Being autotrophic, it prepares its own food.

Option D:

• The Rose plant is an autotrophic plant.
• Being autotrophic, it prepares its own food.

Final answer: The plant which traps and feeds on insects is pitcher plant.

Q2: Plants take carbon dioxide from the atmosphere mainly through their:
(a) Roots
(b) Stem
(c) Flowers
(d) Leaves
Ans: (D)

Plants take carbon dioxide from the atmosphere mainly through their leaves.

Solution: 
Plants take carbon dioxide from the atmosphere mainly through their leaves.
The correct option is D

Explanation of the correct option:

• The gaseous exchange in plants takes place through tiny openings known as stomata.
• The opening and closing of stomata depend upon the surrounding conditions of the environment which is possible with the help of guard cells.
• Stomata are present on the epidermis of leaves.

Explanation of the incorrect options:

Option A:

• Stomata are absent in roots, therefore no gaseous exchange occurs.
• Photosynthesis does not occur in the roots of the plants so they don’t take carbon dioxide.

Option B:

• There may be some stomata present in stems through which gaseous exchange may occur.
• The rate of photosynthesis is very low in a stem so a very less amount of carbon dioxide comes through it.

Option C:

• The stomata present in some flowers are dysfunctional.
• So no exchange of gas in flowers.

Final answer: Plants take carbon dioxide from the atmosphere mainly through their leaves.

Q3: The internal factor affecting the process of photosynthesis is:
(a) Temperature
(b) Chlorophyll
(c) Light
(d) Water
Ans: (b)

Solution:

• Chlorophyll is the green pigment found in plants and is responsible for absorbing sunlight, which is then used to convert carbon dioxide and water into glucose and oxygen, a process known as photosynthesis. 

• If a plant lacks chlorophyll or if the chlorophyll is damaged, the plant will not be able to perform photosynthesis effectively. Therefore, chlorophyll is an internal factor affecting the process of photosynthesis.

• The other options - Temperature (a), Light (c), and Water (d) are all external factors that can affect photosynthesis. Temperature and light intensity can influence the rate of photosynthesis while water is one of the raw materials needed for the process.

Q4: Organisms need nutrition to:
(a) Obtain energy
(b) Fight against diseases
(c) Grow
(d) All of these
Ans: (d)

Explanation:
Just like how we need food to grow, stay healthy and have the energy to do things, all living organisms need nutrition for the same reasons. Here's how:
(a) Obtain Energy: The food we eat is broken down into simpler substances in our bodies. This process releases energy, which is used by the body to perform various functions like moving, thinking, etc.
(b) Fight against diseases: Nutrition provides our bodies with necessary vitamins, minerals and other components that strengthen our immune system, which helps us fight against diseases.
(c) Grow: Food provides nutrients required for the growth and repair of our bodies. For example, proteins help in bodybuilding and repair of wear and tear of tissues.
So, in summary, organisms need nutrition to obtain energy, to grow, and to fight against diseases. Thus, the correct answer is (d) All of these. 

Q5: The chemical used in starch test is:
(a) Safranin
(b) Blue ink
(c) Iodine
(d) Litmus
Ans: (c)
Iodine is the chemical used in starch test.

Q6: Pitcher plant falls in the category of:
(a) Herbivore
(b) Insectivore
(c) Carnivore
(d) None of these
Ans: (b)
Pitcher plant falls in the category of insectivore.

Q7: Parasites:
(a) live on dead organisms
(b) eat animals
(c) prepare their own food
(d) live on other living beings
Ans: (d)
Parasites live on other living beings.

Q8: Water reaches the leaves from the root by:
(a) Stomata
(b) Phloem
(c) Xylem
(d) None of these
Ans: (c)
Water reaches the leaves from root by xylem.

Q9: It is not advisable to sit under the trees at night because:
(a) Carbon dioxide ratio is higher under the trees at night
(b) Trees sleep at night
(c) Plants make food during the night
(d) None of these
Ans: (a)
It is not advisable to sit under the trees at night because carbon dioxide ratio is higher under the trees at night.

Q10: The gas used from the atmosphere during photosynthesis is:
(a) Hydrogen
(b) Nitrogen
(c) Carbon dioxide
(d) Oxygen
Ans: (c)
Carbon dioxide is the gas used from the atmosphere during photosynthesis.

Q11: The ultimate source of energy for all living organisms is:
(a) Plants
(b) Sun
(c) Oxygen
(d) None of these
Ans: (b)
Sun is the ultimate source of energy for all living organisms.

Q12: Product of photosynthesis are:
(a) Carbon dioxide and oxygen
(b) Carbohydrate and carbon dioxide
(c) Carbohydrate and oxygen
(d) None of these
Ans: (c)
Carbohydrate and oxygen are product of photosynthesis.

Q13: A parasitic plant with yellow, slender and tubular stem is:
(a) Pitcher plant
(b) Cuscuta
(c) Sunflower
(d) None of these
Ans: (b)
Cuscuta is a parasitic plant with yellow slender and tubular stem.

Q14: The mode of nutrition in which organisms take in nutrients in solution form from dead and decaying matter is:
(a) Heterotrophic nutrition
(b) Autotrophic nutrition
(c) Saprotrophic nutrition
(d) None of these
Ans: (c)
Saprotrophic nutrition is the mode of nutrition in which organisms take in nutrients in solution form from dead and decaying matter.

Q15: Which of the following shows symbiotic relationship ?
(a) Lichens
(b) Rhizobium bacteria and leguminous plants
(c) Both (a) and (b)
(d) None of these
Ans: (c)
Lichens, Rhizobium bacteria and Leguminous plants both show symbiotic relationship.

Q16: The process by which green plants prepare their own food is known as:
(a) Transpiration
(b) Photosynthesis
(c) Respiration
(d) None of these
Ans: (b)
Photosynthesis is the process by which green plants prepare their own food.

Q17: Stomata are present on:
(a) Stems
(b) Leaves
(c) Flowers
(d) All of these
Ans: (b)
Stomata are present on leaves.

Q18: Which of the following is insectivorous plant ?
(a) Mushroom
(b) Fungi
(c) Pitcher
(d) Cuscuta
Ans: (c)
Pitcher is insectivorous plant.

Q19: Rhizobium is a:
(a) Bacteria
(b) Fungi
(c) Algae
(d) None of these
Ans: (a)
Rhizobium is a bacteria.

Q20: Two different organisms living together and both benefitted from each other, are called as:
(a) Saprophytic
(b) Parasitic
(c) Heterotrophic
(d) Symbiotic
Ans: (d)
Two different organisms living together and both benefitted from each other, are called as Symbiotic.

Q21: Green plants are known as:
(a) Heterotrophs
(b) Autotrophs
(c) Saprotrophs
(d) None of these
Ans: (b)
Green plants are known as Autotrophs.

Q22: Which of the following is not required for photosynthesis:
(a) Sunlight
(b) Water
(c) Oxygen
(d) Carbon dioxide
Ans: (d)
Carbon dioxide is not required for photosynthesis.

Q23: The components of food necessary for our body are:
(a) Carbohydrates
(b) Proteins
(c) Vitamins
(d) All of these
Ans: (d)
The components of food necessary for our body are carbohydrates, proteins, vitamins.

Q24: The gas produced during photosynthesis is:
(a) Oxygen
(b) Carbon dioxide
(c) Nitrogen
(d) None of these
Ans: (a)
The gas produced during photosynthesis is oxygen.

Q25: The solar energy is captured by which part of the plant ?
(a) Stem
(b) Leaves
(c) Root
(d) Flower
Ans: (b)
The solar energy is captured by leaves of the plant.

Q26: The pores on the lower surface of leaf are:
(a) Stomata
(b) Chlorophyll
(c) Xylem
(d) Phloem
Ans: (a)
The pores on the lower surface of leaf are stomata.

Q27: Which of the following is not an end product of photosynthesis ?
(a) Carbon dioxide
(b) Oxygen
(c) Water vapour
(d) Glucose
Ans: (a)
Carbon dioxide is not an end product of photosynthesis.

Q28: The external factor affecting the process of photosynthesis is:
(a) Oxygen
(b) Temperature
(c) Chlorophyll
(d) None of these
Ans: (b)
The external factor affecting the process of photosynthesis is temperature.

Q29: Which part of the plant gets carbon dioxide from the air for photosynthesis ?
(a) Root hair
(b) Leaf veins
(c) Sepals
(d) Stomata
Ans: (d)
Stomata gets carbon dioxide from the air for photosynthesis.

Q30.: Amarbel is an example of:
(a) Autotroph
(b) Parasite
(c) Saprotroph
(d) Host
Ans: (b)
Amarbel is an example of Parasite.