Answer:
The structures that look like powder that the student identified when studying a seed plant are most likely pollen grains.
Step-by-step explanation:
Angiosperms is the name given to plants with seeds, whose characteristic is to reproduce with seeds, in addition to having flowers that have pollen grains.
The pollen is a very small particle -similar to dust- that seed plants present and that corresponds to the male gametophyte of the plant, the haploid phase of the reproductive cycle of them.