Question

Why are pollen grains are well preserved as fossils?

Answer 1

Pollen grains has a prominent two-layered wall. The hard outer layer called the exine is made up of sporopollenin which is one of the most resistant organic material known. It can withstand high temperatures and strong acids and alkali. No enzyme that degrades sporopollenin is so far known. Pollen grains are well-preserved as fossils because of the presence of sporopollenin.

Answer 2

the pollen grain consists of the hardest biolmolecule.....
the sporopollenin.....
it is very hard ....so that pollen grains are well preserved