Which best matches a list that a scientist would make to describe a forest ecosystem?
a. different types of animals and plants, and the forest soil
b. an animal species, the soil, water, and nutrients
c. all the living things in the forest ecosystem
d. different types of soil, rocks, and water sources in the forest

The question is asking "Which best matches a list that a scientist would make to describe a forest ecosystem? " An ecosystem is the total of all animals, plants and of the physical enviroment (soil, etc) in a given place. All of these would have to be present in the description, but it would not be possible to expect the list of all the animals - since for example not all of them are known or classified. So the best answer is A. Different types of animals and plants, and the forest soil