Which term describes the difference in the concentrations of a substance across a cell's membrane?
a. diffusion membrane
b. concentration membrane
c. concentration gradient
d. molcular concentration

Which of the following is most important in making the typical seed more resistant to adverse conditions than the typical spore? a) a different type of sporopollenin b) an internal reservoir of liquid water c) integument(s) d) ability to be dispersed e) waxy cuticle

If a cell's main function is to produce proteins to be excreted, which organelles would you expect to be larger

At which location in earth’s interior does the top density continue to increase as thickness decreases?