Answer :
He was interested in solving medical mysteries at a rather young age.
Explanation: As it said in the first sentence, Barton used the basement as a lab, which leads to the conclusion that he like to experiment. Then it says “where he was raising about one hundred white rats, removing their thymus glands”, so that tells us that he’s interested into that type of stuff as it said in the second to last sentence.
Explanation: As it said in the first sentence, Barton used the basement as a lab, which leads to the conclusion that he like to experiment. Then it says “where he was raising about one hundred white rats, removing their thymus glands”, so that tells us that he’s interested into that type of stuff as it said in the second to last sentence.