cell theory was first proposed in 1838; what major improvement came with the development of the scanning electron microscope?; the cell theory was first proposed in 1838. evidence obtained through additional scientific; which statement best summarizes why the cell theory was developed over time?; prokaryotic cells can be described by which of the following; which statement describes a component of the original cell theory that was removed; the combined observations of mattias; which organelle is involved with homeostasis and storage and is more prevalent in plant cells?