Pollen consists of tiny grains that are the male gametes of plants.
Flowers are the sex organs of certain plants and hold the male and female gamete producing systems.
Pollen consists of tiny grains that are held by flowers.
pollen consists of tiny grains that are held within what
  - bees
  - fruits
  - vegetation
  - flowers
  - lmestone
  - an object
  - loose dirt
  - leaves