An outgroup in a phylogenetic analysis is
- A
A clade nested deep within the ingroup that defines its most recent common ancestor
- B
A taxon recently derived from the ingroup, used to identify the most derived branch
- C
A hybrid lineage placed between sister groups when morphological characters conflict
- Dcheck_circle
A taxon known to have diverged before the group of interest, used to root the tree
Explanation
The outgroup helps determine which traits are ancestral vs derived by serving as an external reference.