Which of the following is a mixture? ​

To confirm when to exclude children from school it’s recommended that you refer to guidelines from which of the following organizations

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

The backbone of the double helix has an alternating molecules. what do you call these alternating molecule?