Question

a group of related organisms that includes an ancestor and all of its descendants is called a(n) ______.
a order
b clade
c kingdom
d phylogenetic tree

Explanation:

To solve this, we analyze each option:

• Option a (Order): A taxonomic rank, not defined by an ancestor and all descendants.
• Option b (Clade): By definition, a clade is a group of organisms consisting of an ancestor and all its descendants.
• Option c (Kingdom): A broad taxonomic group, not defined by lineage of an ancestor and all descendants.
• Option d (Phylogenetic tree): A diagram showing evolutionary relationships, not the group itself.

So the correct answer is the option that matches the definition of a group with an ancestor and all descendants.

Answer:

b. Clade