Answer: Oh boy this is a lot.
Explanation:
1. Organ
2. Nervous tissue
3. Connective tissue
4. Tissue
5. Respiratory system
6. Epithelial tissue
7. Endocrine system
8. Cells
9. Insulin
10. Homeostasis
11. Muscle tissue
12. Organ system
I hope this helps! :)
Answer:
The answer to your question is...
Robert Hooke and Anton van Leeuwenhoek.
