Teacher:You are given a sentence and your task is to generate another sentence that supports the given input.
Teacher: Now, understand the problem? Solve this instance: Features of pollen grains used in identification are size, shape, thickness of the exine (outer wall) and intine (inner wall) of the pollen grain.
Student:
Each pollen grain has two coverings: the exine (thicker, outer layer) and the intine.