What does the process of leaching refers to-

1.	Accumulation of a dark coloured amorphous substance
2.	Organic solvents reabsorbed by the plants
3.	Inorganic solvents get precipitated out of the soil
4.	Water soluble inorganic nutrients go down into the soil horizon and get precipitated as unavailable salts.

In the process of decomposition ‘catabolism’ is performed by-

1. Earthworms

2. Bacteria

3. Bacteria and fungi

4. Fungi

Which of the following statement is incorrect?

Which of the following is the substrate in the process of mineralisation?

1. Detritus

2. Humus

3. Organic matter

4. None of the above

Which of the following does not affect rate of decomposition?

1. Substrate composition

2. Soil moisture

3. Temperature of soil

4. CO₂

Decomposition would be fast if the detritus contains-

1. Cellulose

2. Lignin and chitin

3. Nitrogen and water soluble sugars

4. Cellulose and pectin

Which of the following promotes the process of decomposition?

1. Warm and moist environment

2. low temperature

3. Anaerobiosis

4. Lignin and chitin-rich detritus

What is the source of energy for all ecosystems on Earth, except for the deep sea hydro-thermal ecosystem?

1. Sun

2. Hydrothermal vents

3. Lava

4. Water

What percentage of the incident solar radiation is photosynthetically active radiation (PAR)?

1. 50%

2. Less than 50%

3. More than 50%

4.10%

What proportion of the PAR (photosynthetically active radiation) is captured by plants?

1. 1 - 10%

2. 2 - 10%

3. 5 - 15%

4. 5 - 25%