In which of the following both pairs have the correct combination?

1.	Gaseous nutrient cycle Sedimentary nutrient cycle	Carbon and nitrogen Sulphur and phosphorus
2.	Gaseous nutrient cycle Sedimentary nutrient cycle	Carbon and sulphur Nitrogen and phosphorus
3.	Gaseous nutrient cycle Sedimentary nutrient cycle	Nitrogen and sulphur Carbon and phosphorus
4.	Gaseous nutrient cycle Sedimentary nutrient cycle	Sulphur and phosphorus Carbon and nitrogen

Vertical distribution of different species occupying different levels in a biotic community is

known as 

1. divergence

2. stratification

3. zonation

4. pyramid

Secondary succession takes place on/in

(1) bara rock

(2) degraded forest

(3) newly created pond

(4) newly cooled lava

The mass of living material at a tropic level at a particular time is called

1. Gross primary productivity

2. Standing state

3. Net primary productivity

4. standing crop

Match the following and select the correct option.

     Column I                      Column II

A.  Earthworm                 1. Pioneer species

B. Succession                  2. Detritivore

C. Ecosystem service       3. Natality

D. Population growth        4. Pollination

      A          B         C         D

(1) 1           2         3         4

(2) 4           1         3         2

(3) 3           2         4         1

(4) 2           1         4         3 

Given below is a simplified model of phosphorus cycling in a terrestrial ecosystem with

four blanks (A-D). Identify the blanks.

Secondary productivity is rate of formation of new organic matter by

1. producer

2. parasite

3. consumer

4. decomposer

Which one of the following processes during decomposition is correctly described?

1.  Fragmentation-Carried out by organisms such as earthworms

2.  Humification-Leads to the accumulation of a dark-coloured substance humus, which

undergoes microbial action at a very fast rate

3.  Catabolism-Last  step in the decomposition under fully anaerobic condition

4.  Leaching-Water soluble inorganic nutrients rise to the top layers of soil.

Which one of the following is not a gaseous biogeochemical cycle in ecosystem?

1. Oxygen cycle

2. Phosphorus cycle

3. Nitrogen cycle

4. Carbon cycle

Identify the possible link A in the following food chain

Green plant -> Insect -> Frog -> A -> Eagle

1. rabbit                         

2. wolf

3. cobra                         

4. parrot