Answer:
The layer that contains the youngest fossils is layer A.
Explanation:
In the picture, we have presented four layers and each of them contains one fossil. The rock layers are horizontally arranged and there isn't any disturbance to the layers. Without having disturbances, we have a situation of superposition, basically meaning that the rock layers are arranged in order by age.
The principle of superposition means that the bottom layer of rock strata is the oldest, while the top layer of rock strata is the younges, and all layers between them are arranged from top to bottom as younger to older. In this case, layer A is the one on top, thus it is the youngest layer of rock, and with it, the fossils it contains are the most recent as well. The fossil that we can see is most probably of a carnivorous dinosaur or a very large carnivorous reptilian.
