The term '-globin' refers to what type of biological entity?

The term '-globin' refers specifically to a type of protein that plays a vital role in biological processes. In the context of biology and biochemistry, proteins are essential macromolecules that perform a wide variety of functions within organisms. They are made up of amino acids and are crucial for the structure, function, and regulation of the body’s tissues and organs.

Globins are a family of proteins that include hemoglobin, which is responsible for oxygen transport in the blood, and myoglobin, which carries oxygen in muscle tissues. The presence of the suffix '-globin' is characteristic of proteins involved in oxygen binding and transport, highlighting their functional importance.

Other options such as fat, vaccine, and sugar do not share this specific connection to proteins. Fats are lipids and have different metabolic roles, vaccines are biological preparations that provide immunity, and sugars are carbohydrates. Although all of these biological entities are important, only proteins encapsulated by the suffix '-globin' relate directly to the protein classification, making it the correct answer.