An investigator wishes to use animals in an experiment that involves category b, c, and d activities performed on the same animal. how should the animal be categorized?

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.

How does natural selection change thephenotypes within a population over time?

The united states produces an average of 429 billion pounds of food annually. about 133 billion pounds of that food ends up as waste. the percentage of food that the united states wastes each year is %.