Question

select the text from the paragraph that best helps you understand that assiduous means diligent. there may be more than one correct choice. through careful and thorough research, scientists howard florey and ernst boris chain were later able to use penicillin to develop the first antibiotics—drugs that are used to this day to fight serious infections like pneumonia. thus, although the initial discovery of penicillin occurred by accident, it was ultimately flemings determination to find a cure for bacterial infections and florey and chains assiduous labor that were responsible for the development of these life - saving drugs.

Explanation:

The word "assiduous" is used to describe the labor of Florey and Chain. The context clue "careful and thorough research" (from the first sentence) helps to understand that "assiduous" means diligent. Since "assiduous labor" is parallel to Fleming's "determination", and "determination" implies a strong, persistent effort (similar to being diligent), and the overall idea of working hard (as in developing life - saving drugs through labor) supports the meaning.

Answer:

"careful and thorough research"