What is the function of the type of muscle that is pictured below?

Smooth muscle.
support and movement of the skeleton
movement of food through the digestive system
contraction and relaxation of the heart
generation and conduction of electrical signals

The model illustrates a process by which a substance is taken up by a cell

Why do leaves change color in the fall? green pigments break down and no longer mask the color of chlorophyll. chlorophyll breaks down and no longer masks the colors of other pigments. red- and yellow-colored pigments grow and mask green-colored chlorophyll. green-colored chlorophyll breaks down and turns red and yellow.

Which greenhouse gas is emitted when burn fossil fuels for energy? a. nitrogen b. oxygen c. carbon dioxide d. helium