Question

in a cladogram, when does a group of organisms branch off? when an ancestor becomes extinct when a new trait evolves when it becomes large enough when it is discovered

Explanation:

A cladogram is a diagram used to show evolutionary relationships among organisms. Organisms branch off in a cladogram when a new trait evolves, as this new trait distinguishes a group from its ancestors and other related groups. An ancestor becoming extinct, the group becoming large enough, or being discovered do not relate to the evolutionary branching based on shared derived characteristics (new traits) that define clades.

Answer:

when a new trait evolves