Free Man and His Environment MCQs with Answers

• A. Cyanobacteria
• B. legume-­Rhizobium symbiosis
• C. Mycorrhiza
• D. Azolla pinnata

Explanation: Azolla plays a very important role in rice production. Azolla and its nitrogen-­fixing partner, Anabaena, have been used as green manure…

• A. Insect repellants
• B. Organophosphate and carbamates
• C. Pathogens
• D. Pheromones

Explanation: Pheromones are volatile chemicals produced by a given species to communicate with other individuals of the same species to change their…

• A. Anabaena and Azolla
• B. Cow dung, manure, and farmyard waste
• C. Quick growing crop plowed under soil
• D. None of these

Explanation: Biofertilizers are organisms that bring about nutrient enrichment of the soil.

• A. CO 2 + H 2
• B. CO 2 + H 2 O
• C. CH 4 only
• D. CH 4 + CO 2

Explanation: Biogas or gobar gas is a methane rich fuel gas produced by anaerobic breakdown or digestion of biomass with the help of methanogenic…

• A. Artificial control
• B. Confusion technique
• C. Biological control
• D. Genetic engineering

Explanation: The control of insect pests by the introduction, encouragment and artificial increase of biological agencies like predaceous and parasitic…

• A. A natural herbicide
• B. A natural insecticide
• C. An insect hormone
• D. A bioherbicide

Explanation: Natural insecticides are those which are obtained from microorganisms and plants.

• A. Self perpetuating
• B. Polluting
• C. Very expensive
• D. Toxic

Explanation: The control of insect pests by the introduction, encouragment and artificial increase of biological agencies like predaceous and parasitic…

• A. Azotobacter
• B. Anabaena
• C. Nostoc
• D. Spirogyra

Explanation: Members of Kingdom Monera -­ bacteria and cyanobacteria (blue-green algae)- have the ability to fix nitrogen.

• A. K = N
• B. K > N
• C. K < N
• D. The value of 'r' approaches zero.

Explanation: Asymptote in a logistic growth curve is obtained when population density (N) reaches the carrying capacity (K) i.e., N = K.

• A. Amensalism
• B. Antibiosis
• C. Symbiosis
• D. Fungistasis

Explanation: Mycorrhizae is an association between the roots of plants growing in acid soil and certain fungi.

• A. Large number of progeny with small size.
• B. Large number of progeny with large size.
• C. Small number of progeny with small size.
• D. Small number of progeny with large size.

Explanation: Organisms that are r-­selected (r­-strategists) are able to colonize a habitat rapidly, utilizing the food and other resources before…

• A. Mutualism
• B. Amensalism
• C. Commensalism
• D. Parasitism

Explanation: Parasitism is an association in which one organism (the parasite) lives on (ectoparasitism) or in (endoparasitism) the body of another…

• A. Small animals have a lower O2 requirement
• B. The efficiency of muscles in large animals is less than in the small animals.
• C. It is easier to carry a small body weight
• D. Smaller animals have a higher metabolic rate

Explanation: The small animals have a smaller surface area to body volume ratio. They have higher metabolic rates than larger animals.

• A. C. Darwin
• B. G.F. Gause
• C. Mac Arthur
• D. Verhulst and Pearl

Explanation: Two or more species with closely similar niche requirements cannot exist indefinitely in the same area as sooner or later they come into…

• A. No two species can occupy the same niche indefinitely for the same limiting resources.
• B. Larger organisms exclude smaller ones through competition
• C. More abundant species will exclude the less abundant species through competition.
• D. Competition for the same resources exclude species having different food preferences.

Explanation: Two or more species with closely similar niche requirements cannot exist indefinitely in the same area as sooner or later they come into…

• A. Parasitism
• B. Mutualism
• C. Competition
• D. Predation

Explanation: Competition in ecology refers to the interaction between two or more species that share a common limiting resource, such as food…

• A. Ecosystem
• B. Population
• C. Ecological niche
• D. Biotic community

Explanation: Biological or biotic community is an assemblage of populations of different species of plants, animals, bacteria and fungi which live in a…

• A. Population A produced more offspring than population B.
• B. Population A consumed the members of population B.
• C. Both plant populations in this habitat decreased.
• D. Population B competed more successfully for food than population A.

Explanation: Both the populations are herbivorous, thus they cannot affect each other.

• A. Equisetum
• B. Psilotum
• C. Pinus
• D. Cycas

Explanation: Coralloid roots of Cycas have a symbiotic association with blue­-green algae like Nostoc and Anabaena.

• A. Commensalism
• B. Amensalism
• C. Ectoparasitism
• D. Symbiosis

Explanation: Sea anemone gets associated with the shell of a hermit crab. It provides camouflage and protection to the crab due to the presence of…