2. A scientist analyzing an unknown substance has determined that it consists of carbon, hydrogen and oxygen. During experimentation, she determines that the substance is soluble in oil but not in water.
Which of the following macromolecules is the unknown substance most likely to be?
A
carbohydrate
B.
lipid
C.
nucleic acid
D. protein

Cells a and b are the same size and shape, but cell a is metabolically quiet and cell b is actively consuming oxygen. oxygen will diffuse more quickly into cell because . b the oxygen molecules inside cell b have a higher kinetic energy b. a its membrane transport proteins will not be saturated c. a the diffusion gradient there is shallowerd. b the diffusion gradient there is steeper