When david first came to college, he would get very tipsy after drinking only one beer. three years later, he is known as the "best drinker" in his fraternity, because he can put away a 12-pack without getting very drunk. this ability to ingest more of the substance with a reduced effect is called?

Tolerance

Tolerance is the process whereby repeated and long-term use of a substance causes the user of the substance to no longer respond to it in the way that user initially had responded to it.

Therefore, in David's first year of college when he first started consuming alcohol, he responded to it by becoming "tipsy" after one beer. However, after regularly consuming beer for a long period, after three years, his tolerance to it had increased, and he needed over 12 beers to feel "tipsy"- the way he felt when he first consumed a smaller dose of beer there years ago.