Free Man and His Environment MCQs with Answers

21. The ability of a particular environment that can support maximum individuals is termed as

• A. Uniform distribution
• B. Clumped distribution
• C. Carrying capacity
• D. Density

Explanation: Option C is correct because carrying capacity refers to the maximum population size that a particular environment can sustainably support over time, taking into account available resources and environmental conditions. This term specifically addresses the capacity of an environment to support individuals of a given species, distinguishing it from other concepts such as distribution patterns (options A and B) and population density (option D).

22. Which of the following is not correct for food web?

• A. Start with primary consumers
• B. Formed from food chain
• C. Stable than food chain
• D. Complex than food chain

Explanation: A food web is a graphical representation of interconnected food chains. It shows the feeding relationships and energy flow between different organisms in an ecosystem. A food web starts with primary producers, such as plants, which are then consumed by primary consumers, such as herbivores. The primary consumers are then consumed by secondary consumers, such as carnivores, and so on. Therefore, the statement "Start with primary consumers" is not correct for a food web.

23. Conversion of ammonium into nitrates is:

• A. Nitrification
• B. Nitrogen Fixation
• C. Ammonification
• D. Denitrification

Explanation: Nitrosomonas convert ammonia into nitrates by a process called nitrification. Nitrogen fixation is a process by which molecular nitrogen in the air is converted into ammonia. Ammonification refers to any chemical reaction in which NH2 groups are converted into ammonia or its ionic form, ammonium (NH4+), as an end product.Denitrification is the microbial process of reducing nitrate and nitrite to gaseous forms of nitrogen, principally nitrous oxide (N2O) and nitrogen (N2)

24. In a forest, there are a lot of plants; trees, shrubs, and herbs. What will the Palm trees face if they grow in the same forest?

• A. Intraspecific competition.
• B. Interspecific competition
• C. Environmental competition
• D. All of the above

Explanation: In a forest, palm trees have to face all sorts of competition (intraspecific, interspecific, and environmental). Intraspecific competition is a competition of a species among its own type, palm trees will have to face competition from other palm trees already in that forest. Interspecific competition is competition among different species, palm trees will have to face competition from other species. Environmental competition is the competition exerted by the environment (availability of light, water, and nutrients) on species. Hence option D is correct.

25. The animals that feed on organic debris from decomposing plants and animals are called:

• A. Herbivores
• B. Carnivores
• C. Omnivores
• D. Detritivores

Explanation: Detritivores, also known as detritophages, detritus feeders, detritus eaters, or saprophages, are heterotrophs that obtain nutrients by consuming detritus (decomposing plant and animal parts as well as feces). By doing so, all these detritivores contribute to decomposition and the nutrient cycles.

26. Process ensuring the survival of species over long periods of time, even though individual members of the species die.

• A. Reproduction
• B. Adaptability
• C. Mitosis
• D. Respiration

Explanation: Reproduction is the biological process by which new individual organisms "offspring" are produced from their "parents" Adaptability means being able to rapidly learn new skills and behaviours in response to changing circumstances. Mitosis is a process where a single cell divides into two identical daughter cells. Respiration is a chemical reaction that happens in all living cells, including plant cells and animal cells. It is the way that energy is released from glucose so that all the other chemical processes needed for life can happen.

27. The position of an organism in a food chain of an ecosystem called:

• A. Level of ecosystem
• B. Food chain
• C. Food web
• D. Trophic level
• E. Energy pyramid

Explanation: Option A most likely refers to levels of ecology (since there isn't such a thing as level of ecosystem), which are organism, population, community, ecosystem, biosphere. Option B refers to a food chain which describes the linear transfer of energy from producers to consumers. Option C describes the interconnection of multiple food chains within a certain community. Option D is the correct answer, as it describes the position or the level of a certain organism in a food web or a food chain. Option E is a graphical representation of a food chain, which describes the energy levels and energy transfer from one trophic level to the next.

28. The productivity of aquatic ecosystem is determined by:

• A. Water
• B. Light and nutrients
• C. Light
• D. Nutrients

Explanation: The productivity of the aquatic ecosystem is determined on the basis of availability of light and nutrients to it, hence, option B is correct. Water is present in all aquatic ecosystems regardless.

29. The diagram shows a simplified nitrogen cycle. Which row shows the correct labels for P, Q, R, and S?

• A. Option A
• B. Option B
• C. Option C
• D. Option D

Explanation: The conversion of nitrates in the soil to nitrogen is called the denitrifying(P) process, which is carried out by denitrifying bacteria. Then this nitrogen is fixed(Q) into the legume plants, which can form ammonia either by ammonification by saprotrophic fungi(S) or decay of leaf tissue(R). Hence the answer is A. ( p ) Denitrification. Denitrification is the process that converts nitrate to nitrogen gas, thus removing bioavailable nitrogen and returning it to the atmosphere. Dinitrogen gas (N2) is the ultimate end product of denitrification, but other intermediate gaseous forms of nitrogen exist. ( q ) Legumes can form a symbiotic relationship with nitrogen-fixing soil bacteria called rhizobia. The result of this symbiosis is to form nodules on the plant root, within which the bacteria can convert atmospheric nitrogen into ammonia that can be used by the plant. ( r ) The process of ammonification is carried out by certain bacteria just as Bacillus ramosus, B. vulgaris, Clostridium, Actinomyces, etc. In this process, these organisms release a specific amount of nitrogen compounds like ammonia. However, saprophytic bacteria will not be involved in this process. ( s ) Plant and animal wastes decompose, adding nitrogen to the soil. Bacteria in the soil convert those forms of nitrogen into forms plants can use. Plants use the nitrogen in the soil to grow. People and animals eat the plants; then animal and plant residues return nitrogen to the soil again, completing the cycle.

30. The diagram shows a food web. Which organisms occupy the same trophic level?

• A. 3 and 2
• B. 4 and 1
• C. 5 and 2
• D. 5 and 4
• E. 1 and 2

Explanation: Trophic level is determined by the place the organism occupies after the producer trophic level. Thus, 1 and 2 are both at the same trophic level. Being just at the next position after producer. All other options are incorrect.