A typical prokaryotic cell has about 3,000 genes in its DNA, while a human cell has about 21,300 genes. About 1,000 of these genes are present in both types of cells. How do you explain how such different organisms could have this same subset of 1,000 genes?

Most protists move with the help of flagella, pseudopods, or cilia. Some protists, like the one-celled amoeba and paramecium, feed on other organisms. Others, such as the one-celled euglena or the many-celled algae, make their food by photosynthesis. ... Theyuse pseudopods to move away from bright light or to trap food.