The correct answer would be - oxygen will passively diffuse into the cells.
Explanation:
As the oxygen molecules are very small and has no polarity or no charge they show the passive diffusion through the plasma membrane from the higher concentration to lower concentration inside the cell.
In the lungs the oxygen diffuses out the air sacs into the blood as the air sacs of lungs have higher concentration of oxygen than the blood stream and as the various cells perform the aerobic cellular respiration the concentration of the oxygen inside of the cell become low to the blood so oxygen diffuses into cells.
Thus, the correct answer is - oxygen will passively diffuse into the cells.
There is a balance of resources, shelter, and number of species inside the region which is under consideration. While, the moon jelly's population may increase due to lack of presence of the competition for the resources that are present by means of other consumers of zooplankton that would enhance the growth of the moon jelly's.
Along, with that the decrease in the number of predators which are mainly the big marine animals inside the region that would increase the level or growth of the moon jelly's.