Which mode of medicine is administered "IM"?

The term "IM" stands for intramuscular, which specifically refers to a method of administering medication directly into the muscle tissue. This route allows for the medication to be absorbed more rapidly into the bloodstream compared to other methods, such as subcutaneous injection, where the drug is administered under the skin, or oral delivery, which involves taking the medication by mouth. Intramuscular injections are commonly used for vaccines, hormones, and certain medications that require quick absorption or are too irritating to the tissues if delivered in other ways.

The other choices describe different routes of administration. For instance, administering "in the vein" refers to intravenous injections, which deliver medication directly into the bloodstream, while "under the skin" indicates subcutaneous injections, and "in the mouth" refers to oral medications. Each route has its specific uses and advantages, but for the question at hand, "IM" clearly identifies the intramuscular method.