Question

which best describes a dichotomous key?
each step has two choices.
each step can have any number of choices.
each step describes two possible inferences.
each step is based on genetic traits.

Explanation:

A dichotomous key is a tool used for identification, where at each step, there are two mutually exclusive choices (dichotomous means dividing into two parts). The first option matches this definition. The second is incorrect as it doesn't have "any number" but two. The third is wrong because it's about choices, not inferences. The fourth is incorrect as dichotomous keys can be based on various traits, not just genetic.

Answer:

A. Each step has two choices.