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 :

The impact of immigration on population density is

Match the items in Column I with those in Column II :

Select the correct option from following :

The equation of Verhulst –Pearl logistic growth is From this equation, K indicates:

Given below are two statements :
Statement I: Gause's competitive exclusion principle states that two closely related species competing for different resources cannot exist indefinitely.
Statement II: According to Gause's principle, during competition, the inferior will be eliminated. This may be true if resources are limiting.
In the light of the above statements, choose the correct answer from the options given below :

Mycorrhizae are the example of

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 :

Asymptote in a logistic growth curve is obtained when

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

Gause's principle of competitive exclusion states that:

The impact of immigration on population density is