Question

The outer layer of the pollen grain is thick and made up of a complex, non-biodegradable substance called _______.

Options

• lignin

• cellulose

• pectin

• sporopollenin

Answer 1

The outer layer of the pollen grain is thick and made up of a complex, nonbiodegradable substance called as sporopollenin.

Explanation:

Exine and intine are the two layers that make up a pollen grain. The sporopollenin that makes up the outer layer of exine is hard. It is one of the most durable organic materials ever discovered and is not susceptible to degradation by enzymes, strong acids or alkalis, or higher temperatures.