Each pair of clay balls represents two planetesimals. if each planetesimal is composed of the same material and is separated by the same distance, which pair experiences the greatest gravitational attraction?

smooth muscle is composed of involuntary muscles found within the walls of organs and structures such as the esophagus, stomach, intestines, and blood vessels. those muscles push materials like food or blood through organs. unlike skeletal muscle, smooth muscle can never be under your control.

oxygen, selenium, tellurium, and polonium.

they're all from the same group as sulfur (group 16).