While on the Beagle, Darwin's observations suggested that is (are) a better predictor of relationships among organisms than . a. geological formations; geographic proximity b. geographic proximity; similarity of environment c. fossils; homologies evolutionary d. adaptations; similarity of environmen

B geographic proximity, similarity between the environment

Explanation: During Charles Darwin voyage to America, he did a lot of research about the environment and spent 3years before he returned to England. When he visited the tropical rainforest, he saw many new animals and plants of which he has not seen before. This made him to come to the conclusion that the geographical proximity is better predictor than similarity between the environment.

i think its the first one