What describes each hydrogen bond? A
An attraction between positive ends of two molecules
B
An attraction between the positive end of one molecule and the neg
С
An attraction between neutral ends of two molecules
D
An attraction between negative ends of two molecules

Some birds look for food near cattle and other livestock. the movement of the cattle churns up the ground, making insects available to the birds. the cattle appear to be unaffected by the presence of the birds. what kind of relationship exists between the birds and the cattle? o a. parasitism o b. commensalism o c. predation o d. mutualism

All but one describes an effect of aging on the digestive system. a) decreased acid secretion b) decreased elasticity of stomach c) capacity to resist damage decreases d) food remains in stomach for less time

Explain how the number of similarities between the embryos from early stage to late stage is used as evidence of a common ancestry