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

(1) ectoparasitism

(2) symbiosis

(3) commensalism

(4) amensalism

Asymptote in a logistic growth curve is obtained, when

(1) The value of 'r' approaches zero

(2) K = N

(3) K > N

(4) K < N

Mycorrhizae are the example of

(1) fungistasis                 

(2) amensalism

(3) antibiosis                   

(4) mutualism

Which of the following is correct for r-selected species?

(1) Large number of progeny with small size

(2) Large number of progeny with large size

(3) Small number of progeny with small size

(4) Small number of progeny with large size

If '+' sign is assigned to beneficial interaction, '-' sign to detrimental and '0' sign to neutral interaction, then the population interaction represented by '+' '-' refers to

(1) Mutualism

(2) Amensalism

(3) Commensalism

(4) Parasitism

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

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

The following graph depicts changes in two populations (A and B) of herbivores in 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