Simplify the following text for a Grade 8 native English-speaking person.
Original: Pollen is a fine to coarse powder containing the microgametophytes of seed plants , which produce the male gametes ( sperm cells ) . Pollen grains have a hard coat that protects the sperm cells during the process of their movement between the stamens to the pistil of flowering plants or from the male cone to the female cone of coniferous plants .
Simplified: Pollen is a powder made of pollen grains , which produce sperm cells ( male cells used for reproduction ) of seed plants .