Which scientist developed a theory that describes how light ineracts with gravity

How do the sperm cells get from the stigma to the ovules? a. they slide down the petals to the bottom of the flower. b. they travel through pollen tubes. c. they travel along filaments. d. insects carry the sperm cells from the stigma to the ovules.

Amajor source of energy for your body comes from

What characteristic makes a cell membrane selectively permeable