Cuscuta is an example of
1. predation.
2. endoparasitism.
3. ectoparasitism.
4. brood parasitism.

A sedentary sea anemone gets attached to the sheel lining of hermit crab. The association is
1. ectoparasitism
2. symbiosis.
3. commensalism.
4. amensalism.

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.

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/K is exactly one.
2. when N nears the carrying capacity of the habitat.
3. when N/K equals zero.
4. when death rate is greater than birth rate.

Which of the following is correct for r-selected species?
1. Large number of progeny with large size.
2. Small number of progeny with small size.
3. Small number of progeny with large size.
4. Large number of progeny with small 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. amensalism.
2. commensalism.
3. parasitism.
4. mutualism.

Mycorrhiza are the example of
1. Amensalism.
2. Antibiosis.
3. Mutualism.
4. Fungistasis.

Natality refers to
1. Number of individuals leaving the habitat
2. Birth rate
3. Death rate
4. Number of individuals entering a habitat

Which one of the following population interactions is widely used in medical science for the production of
antibiotics?
1. Parasitism
2. Mutualism
3. Commensalism
4. Amensalism

A keystone species is the one which has
1. A small proportion of total biomass but has huge impact on community’s organisation and survival
2.A plenty of biomass but low impacts on community’s organisation
3. A rare species with little impact on biomass and other species in the community
4. A dominant species which has a large proportion of biomass and which affects many other species