Answer: this is a complex sentence
Explanation:
this is a complex because it is dependent sentence joined with a independent sentence.
if you still don't get it William Humphreys,who was an American meteorologist is complete because it answers who William Humphreys is. the next sentence is dependent because figured out the probable answer 100 years later does not answer who fiqured out the probable answer 100 years later. hope this helps. correct me if i am wrong.
