A) The medical information
Since 1913, the medical knowledge has vastly changed. Medical terms that are today common-knowledge (DNA, chemotherapy, etc.) were not even in existence in 1913.
Hope this helps!!
Tomake better llllllllllllllllllllllllllllllllllll
How about this sentence:
"this task is so difficult, it can only be achieved by a dogged worker"
or "I know that he will get a good result, he is a really dogged sportsman"?
I think that it is the first one
