Question

fix the one word that is used incorrectly.

researchers at queen mary university of london have found that taking one low dose of aspirin everyday could lower the risk of certain cancers.

Explanation:

"Everyday" is an adjective used to describe nouns (e.g., everyday objects). When referring to the frequency of an action (doing something each day), the correct adverb form is "every day", which is two separate words.

Answer:

Replace "everyday" with "every day"
The corrected sentence: Researchers at Queen Mary University of London have found that taking one low dose of aspirin every day could lower the risk of certain cancers.