When does the growth rate of a population following the logistic model equal zero? The logistic model is given as dN/dt = rN(1-N/K)

(1) when N nears the carrying capacity of the habitat

(2) when N/K equals zero

(3) when death rate is greater than birth rate

(4) when N/K is exactly one

Gause's principle of competitive exclusion states that

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

1. ecological niche

2. biotic community

3. ecosystem

4. population

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

(1) Competition

(2) Predation

(3) Parasitism

(4) Mutualism

Most animals are tree dwellers in a 

1. coniferous forest

2. thorn woodland

3. temperate deciduous forest

4. tropical rainforest

Just as a person moving 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 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. 10         

2. 15           

3. 05           

4. zero

Consider the following four conditions (I-IV) and select the correct pair of them as adaptation to environment in desert lizards.
The conditions:
I.  Burrowing in soil to escape high temperature
II. Losing heat rapidly from the body during high temperature
III. Bask in sun when temperature is low
IV. Insulating body due to thick fatty dermis

1. (I) and (III)
2. (II) and (IV)
3. (I) and (II)
4. (III) and (IV)

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

1. Stable population

2. Declining population

3. Expanding population

4. Vanishing population

Which one of the following is categorised as a parasite in true sense?