Question

select the fourth definition in this dictionary entry. concentration \kon - suhn - trey - shuhn\\ noun pl concentrations 1. the amount of a dissolved substance in a given volume: the chemist reduced the concentration of the solution by adding water. 2. a large amount in one location: can you see that concentration of stars in the eastern sky? 3. the ability to focus attention: after mr. olson took a nap, his concentration was improved for the rest of the day. 4. the act of focusing on a single object or activity although it was unusually noisy in the library today, ben didnt lose his concentration. — from latin

Explanation:

The fourth definition in the dictionary entry is clearly labeled as "the act of focusing on a single object or activity".

Answer:

The act of focusing on a single object or activity.