An association of individuals of different species living in the same habitat and having functional interactions is known as:

In which of the following interactions both partners are adversely affected?

The following graph depicts changes in two populations (A and B) of herbivores in a grassy field. A possible reason for these changes is that:

1.	both plant populations in this habitat decreased
2.	population-B competed more successfully for food than population-A
3.	population-A produced more offspring than population-B
4.	population-A consumed the members of population-B

Just as a person moves from Delhi to Shimla to escape the heat for the duration of hot summer, thousands of migratory birds from Siberia and other extremely cold northern regions move to:
1. Western Ghat
2. Meghalaya
3. Corbett National Park
4. Keoladeo National Park

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

1. Symbiosis

2. Commensalism

3. Amensalism

4. Ectoparasitism

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:

According to Darwin, organic evolution is due to: