In wegener's time, scientists thought that the occurrence of fossils of the same organism in two different, disconnected continents was proof that:

a. there had once been land bridges separating the continents.
b. birds flew between the continents and carried the organisms with them.
c. the weather patterns had changed over time such that some organisms could be blown by the wind from one place to another.
d. there were icebergs in the atlantic ocean that could carry organisms from africa to south america