Xerarch and Hydrarch succession leads to respective climax communities as follows-

1. Xeric and hydric

2. Hydric and xeric

3. Mesic and mesic

4. Xeric and mesic

Identify the stages of hydrarch succession.

                      A                                               B
 

1. Reed-swamp stage Marsh-meadow stage

2. Submerged plant stage Scrub stage

3. Reed-swamp stage Submerged plant stage

4. Scrub stage Marsh-meadow stage

The amount of nutrients, such as carbon, nitrogen, phosphorus, calcium, etc. present in the soil at any given time, is referred to as the-

1. Nutrient status of a soil

2. Standing state

3. Standing crop

4. Mineral state.

Standing state does not vary in-

1. Different kinds of ecosystems

2. A seasonal basis

3. Different kinds of soil

4. Same kind of ecosystem.

Why does nutrients are never lost from the ecosystem?

1. Because they get transferred among various trophic levels.

2. Because they get recycled

3. Because they never get exhausted

4. Because they are required in very low quantity.

What do we call to the the movement of nutrient elements through the various components of
an ecosystem ?

1. Recycling

2. nutrient cycling

3. Biogeochemical cycle

4. Both 2 and 3.

Where do we find reservoir for gaseous type nutrient cycling?

1. Land

2. Sea

3. Earth’s crust

4. Atmosphere

Where do we find reservoir for sedimentary type nutrient cycling?

1. Land

2. Sea

3. Earth’s crust

4. Atmosphere

The rate of release of nutrients into the atmosphere is regulated by –

1. pH and moisture

2. Temperature

3. Soil

4. All of the above.

What per cent of the dry weight of organisms constitutes carbon?

1. 17%

2. 28%

3. 49%

4. 67%