The protists belong to the kingdom Protista that comes under the domain Eukarya. Protists are a very broad group, comprising of various eukaryotes that do not fit into the other kingdoms, like animals, plants, and fungi. The protists were the initial eukaryotes.
They would go on to become the precursors for each of the other eukaryotic kingdoms. By examining protists one can witness the transformation between the single-cell prokaryotes and modern multicellular eukaryotes.
Compounds microscope is an optical instrument for forming magnifying images of small objects having an objective Len with a very short focal length. While electron microscope is a high power of microscope uses beam of electron focused by magnetic lenses instead of rays of light.
Answer:
Cell size is limited by a cell's surface area to volume ratio. A smaller cell is more effective and transporting materials, including waste products, than a larger cell. Cells come in many different shapes. A cell's function is determined, in part, by its shape.