16. which of the following are gametes?
a. sperm and embryo
b. ovaries and testes
© sperm and estrogen
d. egg cell and sperm

D. egg cell and sperm

basically gametes make babies and those are the two things you need to create one.

Gametes are the cells used during sexual reproduction to produce a new individual organism or zygote. The male gamete, sperm, is a smaller, mobile cell that meets up with the much larger and less mobile female gamete, egg or ova. Both sperm and egg are only haploid cells. They only carry half of the chromosomes needed.

Explanation:I am the answer giver and this is your answer.

it provides an alternative energy pathway for the reaction to proceed.

a catalyst is a substance that speeds up the rate of a chemical reaction but is not consumed during the course of the reaction.

catalysts increase the rate of reaction without being used up. they do this by lowering the activation energy needed. with a catalyst, more collisions result in a reaction, so the rate of reaction increases. different reactions need different catalysts.

a catalyst works by providing an alternative reaction pathway to the reaction product. the rate of the reaction is increased as this alternative route has a lower activation energy than the reaction route not mediated by the catalyst.