What happens when atp supplies energy for thin filaments in a muscle fiber to slide over the thick filaments?
a. the muscle contracts
b. the muscle relaxes
c. the muscle both contracts and relaxes
d. the muscle neither contracts nor relaxes
hair would be dry and brittle without the presence of
a. sebaceous glands
b. keratin
c. melanin
d. fat
compared with the walls of arteries the walls of capillaries
a. are thicker
b. are thinner
c. lack valves
d. have more resistance

Darrel conducted an experiment with the following procedure: fill two cups with ice water. place an uninflated balloon snuggly onto your left index finger. blow a little air into an identical balloon, and place it onto your right index finger. place both fingers into the cups of ice water. darrel noticed that his right finger felt warmer in the ice water than did his left finger. which of the following does the experiment show? a. air is a good radiator of heat. b. air is a good insulator of heat. c. air is a good conductor of heat. d. air is a good convector of heat.

Anton created a chart listing different types of materials. which best complete the chart?

In many humans, exposing the skin to sunlight over prolonged periods of time results in the production of more pigment by the skin cells (tanning). this change in skin color provides evidence that -