Dichotomous
A dichotomous key is very easy to use because it provides only two choices.
A dichotomous key is a tool that helps the user to determine the identity of unknown organisms or objects. A dichotomous key has two choices that direct the user to the correct name and the right information or characteristics of a given organism. Dichotomous key is used by scientists to place organisms to the group they belong to and it is very helpful when two species or organisms are very similar to one another .