Water is a polar molecule, how is it able to cross the plasma membrane?
a. simple diffusion
b. facilitated diffusion
c. endocytosis
d. active transport

After fertilization, which type of cellular division is responsible for the growth and development of a complex, multicellular organism?

If scientists are wrong about earth's age based on radioactive material and the decay rates are really much faster, how would nuclear power plants be affected?

Which of the following is not a symptom of desertification? a) decrease in salt content of the soil b) lowering of the water table c) reduced surface water d) increased soil erosion e) loss of native vegetation