Claire extends her left calf muscle then relaxes it, concentrating on the tension leaving the muscle as she does so. Claire then tenses and relaxes her left quadriceps, again noting the flow of tension from the area. Claire is engaged in:

What is used to keep track of the gamates and possible offsprings combination

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

Which correctly describes crossing over ?