[" One of the most resistant biological material "],[" present in the exine of pollen grain is "]

The most resistant biological material is

Most resistant biological material is:

The msot resistant biological material is present in the

One of the most resistant known biological material is

One of the most resistant biological materials known is

Exine of pollen grain is formed of

The exine of a pollen grain is composed of one of the most resistant biological materials by which pollen grains are able to wihstand extremes of temperature and dessication and cannot be degraded by any enzyme, is

Exine of pollen grain is made up of

The exine of a pollen grain is composed of one of the most resistant biological matieral by which pollen grains are able to withstand extremes of temperature and dessication and cannot be degraded by any enzyme is