Why were the scientists not able to able to observe most of the cell organelles before 1940?

Before 1940, scientists did not have access to advanced microscopy techniques that could penetrate deep into cells to observe organelles. The technology at that time had limited resolution and magnification, making it difficult to visualize small structures within cells. Additionally, many organelles are transparent or similar in density to the surrounding cytoplasm, making them challenging to distinguish without specialized staining methods.