I would say D.....................
Since chemical spills are very harmful to aquatic/land life for both plants and animals, plants probably wouldn't grow back and animals could be mutated or even killed, decreasing the population of that species. A volcano eruption, can be both good and bad, since a volcano can kill animals and plants, but ash from a volcano is extremely fertile, so plants can regrow, which in turn brings animals back so they can feed on those plants.
The Eurokaya cells are the organelles to convert energy to a usable form
Seeds may be dispersed through animals themselves through feces or wind may carry them. repopulation is the main reason they are dispersed
