Answer:
Option d (Oak bark) is the correct choice.
Step-by-step explanation:
- Throughout 1665, Robert Hooke would be the very first individual who saw cells through some kind of microscopic examination. The innovation as well as advancement and implementation of microscopy allowed this to happen.
- Microscopic constructions would not have been seen already therefore researchers haven't understood which one living creatures were managed to make from.
The other three alternatives are not related to the given particular instance. So that option d would be the correct one.