Which of the following is not a function of predators?

1.	They act as conduits for energy transfer across trophic levels
2.	They keep prey populations under control
3.	They help in the stabilization of the ecosystems
4.	They decrease the species diversity in a community

Very small animals are rarely found in polar region mainly because:

1. Smaller animals have a relatively slower heart rate

2. Smaller animals have a more surface area relative to their volume

3. Smaller animals are invariably herbivores

4. Smaller animals rely on diffusion for exchange of gases with the environment

When the population density reaches the carrying capacity, the logistic growth curve is said to be in:

1. Lag phase

2. A phase of acceleration

3. A phase of deceleration

4. Asymptote

In general, which of the following is not an adaptation seen in parasites in accordance with their life style?

1. Loss of unnecessary sense organs

2. Presence of adhesive organs

3. Low reproductive capacity

4. Loss of digestive system

Organisms with very high intrinsic growth rates have:

1. Long generation times

2. Short generation times

3. No courtship behaviour

4. No carrying capacities

Intraspecific competition is strongest when the:

1. Species overlap in their distribution

2. Populations overlap in their ranges

3. Population is at its carrying capacity

4. Reproductive rate is at its maximum

No predator can become proficient at acquiring prey because:

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