Which type of prohibited substance is known to boost alertness and minimize fatigue among athletes?

Explanation

Stimulants are banned in sports because they increase alertness, reduce fatigue, and improve concentration and endurance, giving an unfair advantage. They act on the central nervous system, boosting energy and reaction time. Examples include amphetamines and ephedrine. WADA prohibits them in competition due to risks like addiction, heart stress, and impaired judgment.