Vertebrates have back bones or spines that give there body support.
When a mutation has an effect that helps a species adapt to an environment, and specimens of both genders have it, it will end up taking over, causing evolution to gradually happen.
Answer: Option B.
Biogeographical
Explanation:
Biogeographical evidence is the evidence that provide information of organisms distribution over geographical areas. It provide information on how and when the organisms evolved and common descent.
Frombthe question, biogeographical evidence will help Darwin make his observation
I belive its called a metric system
