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

1. Ecological niche

2. Biotic community

3. Ecosystem

4. Population

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

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:

1. 15

2. 05

3. zero

4. 10

According to Darwin, organic evolution is due to:

Cuscuta is an example of:
1.  Brood parasitism
2.  Predation
3.  Endoparasitism
4.  Ectoparasitism

What type of human population is represented by the following age pyramid? 

  
1.  Stable population
2.  Declining population
3.  Expanding population
4.  Vanishing population