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

Connection compare and contrast genetic engineering to the process of natural selection. select all statements that are true.

Which statement best describes the role of religion and culture in ancient medicine?

Drag each tile to the correct box. the body monitors the levels of oxygen in the blood to regulate breathing. isabel is running in a marathon and is near the finish line. she feels out of breath. how will her nervous system work to generate a reaction? arrange the tiles in chronological order. isabel's breathing rate increases. sensory receptors in the arteries detect low oxygen levels. the brain sends signals through motor neurons. sensory neurons generate an impulse. the central nervous system relays an impulse to certain brain regions.