In which of the following can a change be directly observed? a. alleles b. genotypes c. phenotypes d. mutations

Animal bodies (and even plant bodies for that matter) are complex enough that life couldn't exist without enzymes. enzymes are usually large, complex biological catalysts that are expensive to make. enzymes speed up the rate of chemical reactions without being used up during the reaction (they can be reused many times). they are highly specific in the reactions they regulate. knowing what enzymes are and how they function, why does this explain why complex life forms could not exist if there were no enzymes.

Will mark brainliest if correct/available! which of the following statements is true? all plants need flowers to sexually reproduce. sexually reproduced offspring are identical to their parents. fertilization always occurs inside the female's body. a body cell has twice the number of chromosomes as an egg cell.

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