A(n) key is very easy to use because it provides only two choices.

Dichotomous key

Explanation:

A dichotomous key is a system that classifies or separates something into different groups. This is done by answering questions about two options, one of the answers opens to two more options and without sequence the process is repeated until the final rating is reached. This system is mainly used in the classification of living beings, facilitating the organization of information!

answer; polycythemia is the correct answer;

a. to encourage apoptosis