Answer:
The correct option is D) In Y
Step-by-step explanation:
Schleiden and Schwann, are known best for bringing up the cell theory. Although there are other scientists such as Robert Hook who are known to have contributed to the cell theory but Schleiden and Schwann are considered to be the pioneer of the cell theory.
Matthias Schleiden was a botanist which means that his expertise was in studying plants. Theodor Schwann was a zoologist which means that his expertise was in studying animals. Hence, Theodor Schwann was the scientist who studies animals and so option, D is correct.