The right option is; D.yes-or-no questions about easily observable characteristics.
A dichotomous key is a tool designed by scientists to help its users to identify a particular type of object and organisms based on physical characteristics. A dichotomous key is divided into two sections and it usually contains specific questions with two choices (yes or no) in each step. When a question is answered, the key guides the user to the next question to ask until the user is able to correctly identify the name of the unknown organism.
