Are specialized plant epidermal cells that lie on either side of stomata. these cells regulate the opening and closing of the stomata they surround and also regulate gas exchange and water loss in the plant tissue.
a)
xylem
b)
phloem
c)
guard cells
d)
tracheid cells

Astudent wants to test the hypothesis that fertilizer improves the growth rate of grass seeds. to test this hypothesis, the student put the same amount of grass seed in 3 containers with the same type of soil. the student measured the growth at the end of the week. all plants received equal amounts of water and sunlight. if you were asked to graph this data, what would you place on the x-axis? a. fertilizer b. water c. plant growth d. week one