(a) Explain primary productivity and the factors that influence it.
(b) Describe how do oxygen and chemical composition of detritus control decomposition .

What is primary productivity ? Explain factors affecting it .

The factor that influences the plants through the physical and chemical composition of the soils is:

Select the correct statement(s) (A) The factors affecting decomposition are chemical nature of detritus and the climatic factors (B) If detritus is rich in lignin, and chitin decomposition is very fast (C ) Decomposition is very slow, if the detritus is rich in nitrogen (D) Detritus is the raw material for decomposition

How many of the following statements are incorrect ? (i) Decomposition is largely an anaerobic process . (ii) Fragmentation , leaching , and catabolism occur simultaneously on detritus. (iii) The vertical distribution of different species occupying different levels is called stratification . (iv) The pond is a deep water body . (v) The rate of decomposition is controlled by the chemical composition of detritus and climatic factors.

(a) Name the type of detritus that decomposes faster. List any two factors that enhance the rate of decomposition. (b) Write the different steps taken in humification and memorisation during the process of decomposition.

(a) Explain the term self pollination and cross-pollination ? (b) How do the insects help in cross- pollination ? (c) How is the process of pollination different from fertilization ?

Explain how changes in prices of other products influence the supply of a given product.