How many genes control a polygenic trait?

Plzz hurry im being timed during times of vigorous physical activity, muscles require a constant supply of oxygen. how does the body respond to these needs? a. breathing rate and heart rate both decrease. b. breathing rate and heart rate both increase. c. heart rate decreases, but breathing rate remains stable. d. breathing rate increases, but heart rate remains stable.

Imagine ? person stepping on a pin and pulling his or her foot way look at the réfléchir arc of the scenarios below

Contrast how pollination is different among gymnosperms and angiosperms.