All Free Biology MCQs with Answers

• A. Gambusia
• B. Rohu
• C. Clarias
• D. Exocoetus

Explanation: Gambusia affinis is regarded as a larvicidal fish as it selectively feeds on mosquito larvae. It forms an effective tool for biological control of mosquitoes.

• A. A. indica is largest wild honey bee.
• B. Wax is waste material of honey bee.
• C. Workers are the smallest of the three castes.
• D. The drone of the honey bee is diploid.

Explanation: A highly organised division of labour is found in the colony of honey bees. A good and well developed colony of bees has 40 to 50 thousand individuals consisting of 3 castes viz., queen, drone and worker. Although the workers are the smallest of the three castes, they function as the main spring of a complicated machinery like the honey bee colony. It takes 21 days in the development from the egg to the adult and the total life span of a worker is about 6 weeks. The workers are atrophied female which sacrifice themselves for the well­-being of the colony. The total indoor and outdoor duties of the colony are performed by the workers only. Apis dorsata is the largest honey bee and A. indica is slightly smaller than it. Beeswax is a by-product of honey bees and the drone of honey bees is haploid in nature.

• A. Sesbania
• B. Bacillus popilliae
• C. Anabaena
• D. Bacillus subtilis

Explanation: Azolla plays a very important role in rice production. Azolla and its nitrogen-­fixing partner, Anabaena, has been used as green manure to fertilize rice paddies and increase production. With the help of Azolla, rice can be grown year after year, several crops a year, with little or no decline in productivity; hence no rotation of crops is necessary.

• A. Inland fisheries
• B. Aspergillosis
• C. Marine fisheries
• D. Both (a) and (c).

Explanation: Aquaculture involves the production of useful aquatic plants and animals such as fishes, prawns, shrimps, lobsters, crabs, molluscs by proper utilization of small and large bodies of water. The production of fishes is called pisciculture. Inland fishery deals with the fishery aspects of waters other than marine water. Marine fishery deals with the fishery aspects of the sea water or ocean.

• A. Gambusia
• B. Cutter fish
• C. Anabus
• D. Rohu.

Explanation: Gambusia affinis is regarded as a larvicidal fish as it selectively feeds on mosquito larvae. It forms an effective tool for biological control of mosquitoes.

• A. 6 weeks
• B. 10 weeks
• C. 10 days
• D. 15 days.

Explanation: A highly organised division of labour is found in the colony of honey bees. A good and well developed colony of bees had 40 to 50 thousand individuals consisting of 3 castes viz., queen, drone and worker. Although the workers are the smallest of the three castes they function as the main spring of complicated machinery like the honey bee colony. It takes 21 days in the development from the egg to the adult and the total life span of a worker is about 6 weeks. The workers are atrophied female which sacrifice themselves for the well­-being of the colony. The total indoor and outdoor duties of the colony are performed by the workers only. Apis dorsata is the largest honey bee and A. indica is slightly smaller than it. Beeswax is a by-product of honey bees and the drone of honey bees is haploid in nature.

• A. Only cells having oncogenes
• B. Product of spore formation in bacteria
• C. Nervous cells of frog
• D. Hybrid cells resulting from myeloma cells.

Explanation: Hybridoma is a hybrid cell resulting from the artificial fusion of an antibody­-producing lymphocyte and a myeloma cell from a lymphoid tumour. Such cells can produce a clone that may be maintained in tissue culture and used for the continuing production of the monoclonal antibody.

• A. They are more resistant to diseases
• B. Once a desired hybrid produced, no chances of losing it
• C. They can be easily propagated
• D. They have a longer life span.

Explanation: Hybrid vigour or heterosis is defined as the superiority of the hybrid over its parents. It is lost on inbreeding. It is lost in the F2 generation in self-pollinated plants and declines slowly in cross-pollinated plants. So it is more profitable in vegetatively propagated plants as they do not involve sexual reproduction and so hybrid vigour is not lost in subsequent crops, e.g., sweet potato, sugarcane, strawberry and grapes, etc.

• A. Immunization
• B. Genetic engineering
• C. Tissue culture
• D. Biotechnology.

Explanation: Genetic engineering is the experimental manipulation of genetic material, especially for industrial or medical uses. It encompasses the techniques of gene cloning, the modification of DNA by changes in sequence arrangement or deletion, and the introduction of novel genes into cells and organisms. It may prove possible to advantageously modify the genes of farmed animals, to correct genetic deficiencies of the human by inserting novel genes. This can be done by breakage of a DNA molecule at two desired places into another DNA molecule of the desired animal.

• A. Inbreeding
• B. Euthenics
• C. Eugenics
• D. None of these.

Explanation: Euthenics is the suitable environment for human well being, health and intellect.Inbreeding involves production of progenies by mating between relatives.