Question

Why do you think the exine should be hard? What is the function of germ pore?

Answer 1

Yes 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.
Through germ pore pollen tube develops and comes out.

Answer 2

Exine is the outer coating of a pollen grain or a spore. It is decay-resistant and is one of the two layers that are formed on pollen grains. It needs to be tough and hard in order to protect the inner Pollen which will later on need to fertilize.
On the other hand, Germ Pore is a thin area and a pore in the outer wall of the pollen grain or a spore. This is the area from where the germ tube or a pollen tube exits through during germination