The· eyes of Octopus and eyes of cat show different patterns of structure, yet they perform similar function. This is an example of

• homologous organs that have evolved due to convergent evolution

• homologous organs that have evolved due to divergent evolution

• analogous organs that have evolved due to convergent evolution

• analogous organs that have evolved due to divergent evolution

82.

Infection of Ascaris usually occurs by

• drinking water containing egg of Ascaris

• eating imperfectly cooked port

• tse-tse fly

• mosquito bite

The cell-mediated immunity inside the human body is carried out by

• T-lymphocytes

• B-lymphocytes

• thrombocytes

• erythrocytes

In plant breeding programmes, the entire collection (of plants/seeds) having all the diverse alleles for all genes in a given crop is called

• selection of superior recombinants

• cross- hybridisation among the selected parents

• evaluation and selection of parents

• germplasm collection

During sewage treatment, biogases are produced, which include

• methane, hydrogen sulphide and carbon dioxide

• methane, oxygen and hydrogen sulphide

• hydrogen sulphide, methane and sulphur dioxide

• hydrogen sulphide, nitrogen and methane

A biologist studied the population of rats in a barn. He found that the average natality was 250, average mortality 240, immigration 20 and emigration 30. The net increase in population is

• 10

• 15

• 05

• Zero

Which one of the following processes during decomposition is correctly described?

• Fragmentation - Carried out by organisms such as earthworm

• Humification - Leads to the accumulation of a dark coloured substance humus, which undergoes microbial action at a very fast rate

• Catabolism - Last step in the decomposition under fully anaerobic condition

• Leaching - Water soluble inorganic nutrients rise to the top layers of soil

A sedentary sea anemone gets attached to the shell lining of hermit crab. The association is

• ectoparasitism

• symbiosis

• commensalism

• amensalism

Global warming can be controlled by

• Reducing deforestation, cutting down use of fossil fuel

• Reducing reforestation, increasing the use of fossil fuel

• Increasing deforestation, slowing down the growth of human population

• Increasing deforestation, reducing efficiency of energy usage

The Air Prevention and Control of Pollution Act came into force in

• 1975

• 1981

• 1985

• 1990