What is the type of injection that is given directly into a vein?

The correct answer is the type of injection that is given directly into a vein is known as intravenous. This method of administration allows for medications, fluids, or nutrients to enter the bloodstream immediately, ensuring rapid absorption and effect. Intravenous injections are commonly used in medical and veterinary practices because they can provide immediate results, which is crucial in emergencies or when a fast-acting response is needed.

In contrast, intramuscular injections involve delivering substances into a muscle, which takes longer to absorb compared to intravenous injections. Subcutaneous injections are administered into the tissue layer between the skin and muscle, having an even slower absorption rate. Intradermal injections are given into the dermis, just below the epidermis, and are typically used for allergy testing or local anesthesia, rather than systemic administration. Each method has its specific uses based on the required speed of absorption and the desired effect of the medication.