How does the structure of dendrites relate to their function in the nervous system?

They are long so they can stretch throughout the body.

The question is asking how has the study of mitosis affected scientists’ knowledge of cancer. Mitosis is a type of cell division ( so we reject answer c, since it doesn't have to do with cell division) and what we want is to have the cells divide slower (so we reject answer a), but unfortunately, we don't know how to do it yet (so we reject answer d) - the correct answer is: It led to an understanding of how cancer cells divide so rapidly.