Your teacher gives you a task in science class. You must decide which of the five samples you are given are alive or were once alive. One specimen is a crusty gray-green object. What is the BEST clue you could use to decide: living thing or not a living thing?
A)
Does it move?
B)
Does it have DNA?
Is it made of cells?
D)
Can it make its own food?

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