Zooplanktons are :

• parasites

• primary producers

• primary consumers

• primary decomposers

When one organism is benefited without affecting the other, it is called

• parasitism

• commensalism

• saprophytis

• symbiosis

The equation $\frac{∆{\mathrm{N}}_{\mathrm{n}}}{\mathrm{N}∆\mathrm{t}}$= B represents, which of the following?

• Natality

• Growth rate

• Mortality

• All of these

What are mycorrhizae?

Scirpophage incertulus is an example of

• monophagus pest

• diphagus pest

• oligophagus pest

• polyphagus pest

Which one of the following is a population?

• A spider and some trapped flies in its web

• Earthworm that lives in a grassland along with other arthropods

• All the plants in a forest

• All the oak trees in a forest

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

188.

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

• ectoparasitism

• symbiosis

• commensalism

• amensalism

The resting state of reptiles in winter is

• hibernation

• aestivation

• diapause

• moulting

Given below is the survivorship curve of different population.

Which type of the curve has the highest chances of senescence affecting mortality?

• Type I

• Type I and II

• Type III

• Type I, II and III