Organisms and Populations — BIOLOGY STD 12 Science — Question

Read the following and answer any four questions from (i) to (v) given below:
During teaching about various environmental factors, a teacher draw a figure that depicts like history strategies for three plant species (X, Y and Z) along 3 axes - strength of competition with other organisms, level of disturbance in the habitat and level of environmental stress in the habitat. Species X grows in habitats where competition among species is high but disturbance and stress are low. Species Y grows in habitats with high environmental stress but with low intraspecies competition. Species Z grows in highly disturbed habitats with low environmental stress.

1. Which of the following is correct regarding plant type X?

1. It has slow growth rate.
2. It lives in area with high probability of severe environmental changes.
3. It has good competitive ability at low population densities near the carrying capacity.
4. None of these.

2. Environmental stress occurs through.

1. Very low temperature.
2. Drought.
3. Nutrient deficiency.
4. All of these.

3. Select the correct option regarding plant type X, Y and Z.

1. X type of plants are likely to be trees.
2. Y type of plants could be desert plants.
3. Z type of plants could be herbaceous plant.
4. All of these.

4. Y type of plants grow under high stress and:

1. Produce large number of seeds in a short time after rains.
2. Have rapid growth.
3. Produce less number of seed in a long time after rain.
4. Both (a) and (b).

5. Assertion: Plant growth rate is high in area of high stress and high disturbance.

Reason: High stress and high disturbance promote breeding capacity in plants.

1. Both assertion and reason are true and reason is the correct explanation of assertion.
2. Both assertion and reason are true but reason is not the correct explanation of assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.