Which of the following would appear as the pioneer organisms on bare rocks?

1.	Liverworts	2.	Mosses
3.	Green algae	4.	Lichens

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

During ecological succession:

The vertical distribution of different species occupying different levels in a biotic community is known as:

Secondary succession takes place on/in:

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

In an ecosystem, the rate of production of organic matter during photosynthesis is termed as:

1. net primary productivity

2. gross primary productivity

3. secondary productivity

4. net productivity

Match the following and select the correct option: 

1. A-(i), B-(ii), C-(iii), D-(iv)

2. A-(i), B-(ii), C-(iii), D-(iv)

3. A-(iii), B-(ii), C-(iv), D-(i)

4. A-(ii), B-(i), C-(iv), D-(iii)

Given below is a simplified model of phosphorus cycling in a terrestrial ecosystem with four blanks (A-D). Identify the blanks.