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.
I can certainly see how this is likely to be a science book. With the latest photographic technology scientists have photographed everything from star nebulas, space gases, to exoskeletons of creatures, flowers, sun flares, waves in motion, inside cells, etc. so yes absolutely!
B, ocean trenches are formed after a underwater volcano has erupted.<span />
The middle question is the nucleus, transcription takes place in the nucleus while translation happens in the cytoplasm
The human digestive system can fail if you eat something harmful, and it can break down nutrients, techinically the digestive system can stop working if you get something like Gastoparesis, which stops the movement of food through the digestive system.