The World of Living - 1 - Free MCQ Practice Test with solutions, CTET Science

Diversity refers to the variety of organisms (plants, animals and microorganisms) existing on the earth.

Insect bodies have openings, called spiracles, along the thorax and abdomen. These openings connect to the tubular network, allowing oxygen to pass into the body, regulating the diffusion of CO₂ and water vapor. 

Camel shows adaptation like hump on back, passes scanty of urine and the padded soles. Camel perspires(sweat) less to reduce water loss.

The process of fusion of male and female gametes is called fertilization. The fusion of male and female gametes, also known as sperm and ovary, usually occurs in the fallopian tube of the female reproductive system. The cell that results from the fusion of the gametes is called a zygote. The zygote divides multiple times to form the embryo inside the seed.

• Nitrogen Cycle: The nitrogen cycle is the process by which nitrogen is converted between its various chemical forms, such as nitrate, nitrite, and ammonia, in the environment. It involves several key steps, including nitrogen fixation, nitrification, denitrification, and ammonification.


• Nitrogen Fixation: Nitrogen fixation is the process by which nitrogen gas from the atmosphere is converted into ammonia or other usable forms by certain bacteria and cyanobacteria.


• Nitrification: Nitrification is the process by which ammonia is converted into nitrites and then nitrates by bacteria in the soil.


• Denitrification: Denitrification is the process by which nitrates are converted back into nitrogen gas by bacteria, thereby returning nitrogen to the atmosphere.


• Ammonification: Ammonification is the process by which organic nitrogen compounds are converted into ammonia by decomposers, such as bacteria and fungi.


• Balance in the Atmosphere: The nitrogen cycle helps maintain a balance of nitrogen in the atmosphere by ensuring that nitrogen is constantly being converted between different forms and being recycled through various processes. This prevents nitrogen levels from becoming depleted or excessive in the environment.

Shape, size and other features of plants depend upon surroundings of the living things.

Stomata are microscopic pores found on the surface of leaves and are responsible for gas exchange.
They allow plants to take in carbon dioxide and release oxygen, playing a crucial role in photosynthesis and respiration.

Pasteurization is a process in which milk is heated to about 70oC for 15 to 30 seconds and then suddenly chilled and stored. By doing so, it prevents the growth of microbes. This process was discovered by Louis Pasteur and hence is called pasteurization.

Explanation of the correct option :

1. Abiotic means non-living components such as air, water, soil, light and temperature.
2. From the above options, tree is a living component.
3. So it is not an abiotic component.

Explanation of the incorrect option:

Option A: Soil is an abiotic component.

Option B: Air is an abiotic component.

Option C: Temperature is an abiotic component.

Final answer: Tree is not an abiotic component.

Human male germ cell is called sperm. Sperm is produced inside the testes. Sperm contain head and long tail that help them to swim.

• Tuberculosis: Tuberculosis is a bacterial infection caused by the bacterium Mycobacterium tuberculosis. It primarily affects the lungs but can also affect other parts of the body.

• Transmission: Tuberculosis is spread through the air when an infected person coughs, sneezes, or talks. The bacteria are released into the air and can be inhaled by others.


• Symptoms: Symptoms of tuberculosis include coughing, chest pain, weight loss, fatigue, and fever. It can be a serious condition if left untreated.


• Diagnosis: Diagnosis of tuberculosis involves a combination of medical history, physical examination, chest X-ray, and laboratory tests such as sputum culture.


• Treatment: Tuberculosis is treated with a combination of antibiotics for a specified period of time. It is important to complete the full course of treatment to prevent drug-resistant strains of the bacteria.

Therefore, tuberculosis is a disease that is spread due to bacteria, specifically Mycobacterium tuberculosis.

During mitosis, a single parent cell divides into two identical daughter cells, each with the same number of chromosomes as the parent cell. The process of mitosis is divided into several stages, including prophase, prometaphase, metaphase, anaphase, and telophase. During these stages, the chromosomes in the cell's nucleus are replicated and then separated into the two daughter cells, ensuring that each daughter cell receives a complete set of genetic information.

During transpiration, the excess of water absorbed by the roots of plants get evaporated through stomata.

• Tuberculosis: Tuberculosis is caused by bacteria, specifically Mycobacterium tuberculosis, not protozoa.


• Polio: Polio is caused by the poliovirus, not protozoa.


• Malaria: Malaria is a disease caused by protozoa of the genus Plasmodium. These parasites are transmitted to humans through the bites of infected mosquitoes.


• Typhoid: Typhoid fever is caused by the bacterium Salmonella typhi, not protozoa.

• Out of the options provided, the disease caused by protozoa is Malaria.


• Malaria is a serious and sometimes fatal disease that is prevalent in tropical and subtropical regions.


• Preventive measures against malaria include the use of insect repellent, bed nets, and antimalarial medications.

The process of fusion of male and female gamete is called fertilization. Fertilization may be internal or external depending upon organism.

The age between 13 years to 19 years is called teenage. During this age, a number of physiological and morphological changes take place in the children.

While baking cakes, yeast reproduces rapidly and produces carbon dioxide gas. This gas is responsible for the spongy texture of cake.

Antibiotics are the medicines that kill or stop the growth of disease-causing microorganisms. Streptomycin, tetracycline and erythromycin are some of the commonly known antibiotics which are made from fungi and bacteria. Antibiotics are mostly effective against bacterial diseases. Among the diseases given, only typhoid is caused by bacteria, i.e., Salmonella typhi, whereas all the other diseases are caused by protozoa or viruses.

During aerobic respiration, complete oxidation of food takes place and more energy is released in form of ATP.

Budding is a mode of asexual reproduction in which a small outgrowth develop on body surface that enlarge and get separated from parent body. Budding takes place in hydra and yeast.

• Budding is a type of asexual reproduction in which a new organism develops from an outgrowth or bud due to cell division at one particular site. The small bulb-like projection coming out from the yeast cell is called a bud.
• Organisms such as hydra use regenerative cells for reproduction in the process of budding.

• Living organisms which are invisible to the naked eye are called microorganisms. Microorganisms are too small to be seen with our naked eyes. They can be seen only through a device known as a microscope.

Asexually produced identical organisms are called clone. They contain similar characteristics.

Anaerobic respiration occurs in the absence of oxygen and is less efficient than aerobic respiration. Unlike aerobic respiration, the end products here are ethyl alcohol as in yeasts and lactic acid as in animal cells. So the answer is 'Alcohol and lactic acid'.

Frogs are unique creatures that can breathe through both their skin and lungs. This ability allows them to take in oxygen efficiently, especially when they are in water.

Here are some key points about frogs' breathing:

• Skin respiration: Frogs can absorb oxygen directly from the water through their skin.
• Lung respiration: When on land, they primarily use their lungs to breathe air.
• Moist skin: Their skin needs to remain moist for effective oxygen absorption.

This dual method of breathing helps frogs survive in various environments, making them fascinating amphibians.

A vaccine is a biological preparation containing weakened or dead microbes. It is introduced into a healthy person’s body so that it can produce antibodies against the disease-causing microbes. Vaccines can be injected or administered orally.

In human beings, a single matured egg is released into the oviduct by one of the ovaries every month.

• In ecology, a habitat is the type of natural environment in which a particular species of organism lives.
• Every organism has certain habitat needs for the conditions in which it will thrive, but some are tolerant of wide variations while others are very specific in their requirements.
• A habitat is not necessarily a geographical area, it can be the interior of a stem, a rotten log, a rock or a clump of moss, and for a parasitic organism it is the body of its host.

• Aerobic respiration: This is the process by which glucose is broken down in the presence of oxygen to produce energy in the form of ATP.


• Steps of aerobic respiration:
  
  
  
  • Glycolysis: Glucose is broken down into pyruvate.
  
  
  • Krebs cycle: Pyruvate is further broken down to produce ATP, CO2, and high-energy electrons.
  
  
  • Electron transport chain: High-energy electrons are used to produce a large amount of ATP.
  
  
  
  


• Importance of oxygen: Oxygen is essential for the final step of aerobic respiration, the electron transport chain, where the majority of ATP is produced.


• Energy production: Aerobic respiration is much more efficient in producing ATP compared to anaerobic respiration, which produces ATP through glycolysis only.


• Overall efficiency: Aerobic respiration allows for the complete breakdown of glucose, resulting in the maximum amount of energy production per glucose molecule.

Gills are respiratory organs in fish. Gills intake oxygen from water.