GENERAL KNOWLEDGE

Detailed explanation-1: -The exine is chiefly composed of a class of material called as sporopollenin. Chemical analysis has revealed that it is a mixture of biopolymers, containing long chain fatty acids, phenylpropanoids, phenolic compounds and carotenoids. It is derived from carotenoids by oxidative polymerization.

Detailed explanation-2: -(d)Fatty substance. Hint: Sporopollenin is the most resistant known biological material that is found in the exine of the pollen grains. Sporopollenin is resistant to chemical and microbial decomposition. The pollens are well preserved and conserved due to this during fossilization.

Detailed explanation-3: -Sporopollenin is a biopolymer consisting of long chain fatty acids and phenolic compounds along with others.

Detailed explanation-4: -Sporopollenin is a lipid-and phenolic-based polymer present in the outer exine layer of pollen walls (Morant et al., 2007). Similarly, suberin is a lipid-and phenolic-based polymer present in the cell walls of various external and internal tissue layers (Franke & Schreiber, 2007).