What does an Electrocardiogram do? A. Measures the electrical activity of a heart by measuring the current in the skin above it.
B. Pill that contains 3 grams of electrochemical material that helps keep the electrical current in the heart balanced.
C. Measures how much electrical current can be passed through a heart before it stops beating.
D. Restarts the heart by sending an electrical pulse through it.

It actually measures the electrical activity

Explanation:

They are sticky wires that they put on your arms and chest etc

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.

i'm thinking (a) to keep sand in place; ////////////

explanation: a sand fence or sandbreak, like a snow fence, is used to force windblown, drifting sand to accumulate in a desired place. sand fences are employed to control erosion, sand dune stabilization, keep sand off roadways, and to recruit new material in desert areas.