Lead is toxic, but do you know why?
a. lead is toxic mainly because it preferentially replaces other metals in biochemical reactions.
b. in so doing it interferes with the proteins that regulate blood pressure, heme production (which can lead to anemia) and sperm production.
c. lead also displaces calcium in the reactions that transmit electrical impulses in the brain, which diminishes the ability to think and recall information.

Red flowered snapdragons are crossed with white flowered snapdragons, producing all pink snapdragons in the f1 generation. what would you expect if you crossed pink with pink? 3/4, 1/4, 1/2 red, 3/4,/1/2,/1/4 pink,1/2, 3/4, 1/4 white

Research question: why are the carrots that grew on the left side of the garden larger than the carrots that grew on the right side of the garden? which hypothesis is based on this research question? a comparison of people with gardens to people without gardens will show who is likely to live longer. b. carrots are thought to be good for your eyesight and should be eaten regularly. c. carrots that are provided lots of sunlight grow to a larger size than carrots grown in the shade. d. eating fresh vegetables every day is a healthy thing to do.

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.