The two cells of the similar shape, and size have different levels of the ongoing metabolic activity. On one hand, the cell a is metabolically quiet, which means that no energy consuming chemical reactions are taking place in this cell. On the other hand, the cell b is actively consuming the surrounding oxygen. In this scenario, the oxygen will more quickly diffuse into the cell b because the diffusion gradient for oxygen in this cell is steeper than in the cell a.
Hence, the blanks can be filled with 'b and the diffusion gradient is steeper' respectively.
Neurotransmitters are chemicals released at axon terminals to a target cell to continue to action potential
Evolution is not a random process. The genetic variation
on which natural selection acts may occur randomly, butnatural selection itself is not random at all.
Both nucleic acids have Adenine, Cytosine and Guanine. DNA has an exclusive Thymine while RNA has Uracil which DNA doesn't have.
