Answer:
The invention of the electron microscope allowed them to see organelles and other structures smaller than cells. There is variation in cells, but all cells have a plasma membrane, cytoplasm, ribosomes, and DNA. These similarities show that all life on Earth has a common ancestor in the distant past
Rough ER - protein synthesis, transport of proteins throughout the cell
Smooth ER - lipid synthesis and cell detoxification
The uterus, specifically the Fallopian tube.
