The alveoli in the lungs have very thin surface membranes which are often made out of a single layer of cells. the alveoli in the lungs are used by the body for the exchange of

a.
nutrients
b.
energy
c.
gases
d.
liquids

Are the earth's ocean floor and continents the same age geologically? why or why not?

Beth’s hygrometer is reading a temperature of 30 c and a relative humidity of 65%. the humidity in the air is?

Multicellular organisms use cell division, mitosis, for growth and the maintenance and repair of cells and tissues. single-celled organisms may use cell division as their method of reproduction. regardless of the reason for mitosis, the process ensures genetic continuity. what is the step in the cell cycle that ensure genetic continuity?