Why are horses and donkeys in different species

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.

Hurry where is the majority of earth's water found? o glaciers o oceans ground o rivers and lakes

Crossing over and independent assortment are important activities that occur during meiosis. what is the significance of these activities