Final answer:
Onion root tip and whitefish blastula are used to study mitosis because they are actively dividing tissues and can provide clear observations of the different stages of mitosis under a microscope.
Step-by-step explanation:
The onion root tip and whitefish blastula are commonly used to study mitosis because they are both actively dividing tissues, making it easier to observe and study the different stages of mitosis.
Onion root tips are constantly growing, and the cells at the root tip undergo rapid mitotic divisions as part of root growth. The cells are easy to obtain and have large, clear chromosomes that are visible under a microscope.
Similarly, whitefish blastula is a stage in the development of fish embryos where there is active cell division. By examining cross-sections of the blastula under a microscope, scientists can observe different stages of mitosis to better understand the process.