Need chemistry asap! which of the following statements regarding chemical equilibrium is not necessarily true?

a.) equilibrium is shown using a double arrow.
b.) when a system is at equilibrium, it continues to react both ways (forward and reverse).
c.) at equilibrium, the amounts of reactants equal the amounts of products. d.) at equilibrium, particle-level changes are occurring.

need an answer as soon as possible! so much!

What kind of ion is contained in salts that produce an acidic solution? a positive ion that attracts a proton from water a positive ion that releases a proton to water a negative ion that attracts a proton from water a negative ion that releases a proton to water

Chen drew a diagram to compare the ways in which different organisms obtain nitrogen. which label belongs to the area marked z?

Effect of rotenone and antimycin a on electron transfer rotenone, a toxic natural product from plants, strongly inhibits nadh dehydrogenase of insect and fish mitochondria. antimycin a, a toxic antibiotic, strongly inhibits the oxidation of ubiquinol. (a) explain why rotenone ingestion is lethal to some insect and fish species. (b) explain why antimycin a is a poison. (c) given that rotenone and antimycin a are equally effective in blocking their respective sites in the electron-transfer chain, which would be a more potent poison? explain.