Question

why exine should be hard?​

Answer 1

Answer:

Exine should be hard because it protects pollen grain (by which pollen grain develops normally) from severe conditions. It is the outermost layer made up of sporopollenin which protects pollen grain from harsh environmental conditions.

Answer 2

Answer:

exine should be hard because it is performing a crucial task of protecting pollen grains.

hope it helps mate...