You participate in a sleep study at a university clinic. the researchers measure your body chemistry while you are sleeping. which hormone do they find follows a circadian rhythm and peaks just before you wake?

The hormone they would measure is melatonin. In animals, this is a hormone produced by the pineal gland which regulates sleep, but has an anti-oxidant function in plants. Melatonin synchronizes the circadian rhythms of animals including timing of wakening and regulation of blood pressure.

one characteristic that is shared by all is a soft body. many

of these invertebrate animals also have an outer shell to protect their

body. oysters, clams, snails, and mussels are all mollusks. so are octopuses, squids, and slugs. mollusks live on land and in freshwater.