The horizontal axis of the cladogram depicted below is a timeline that extends from 100,000 years ago to the present; the vertical axis represents nothing in particular. The labelled branch points on the tree (V-Z) represent various common ancestors. Let's say that only since 50,000 years ago has there been enough variation between the lineages depicted here to separate them into distinct species, and only the tips of the lineages on this tree represent distinct species. 
In Darwin's tree of life, each fork in the tree represents ________.
Definitions:
Control
The power or authority to direct, manage, or govern actions or outcomes.
Questionnaire
A structured series of questions used to gather information from respondents for research purposes.
Written Interview
A method of gathering information or assessing qualifications where questions are sent in written form for the respondent to answer also in writing.
Type
A category or class of people or things with common characteristics or attributes.
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