Final answer:
Recognition proteins display unique patterns of carbohydrates that are essential for cell identification and immune responses, distinguishing self from non-self cells.
Step-by-step explanation:
The recognition proteins give cells their identity. They have a unique pattern of carbohydrates attached to them, which helps identify a cell as part of a tissue or part of an organism. The correct answer is B) Recognition; carbohydrates. These proteins, along with carbohydrates, form the glycocalyx, which functions as a cellular identity marker. Carbohydrates are found on the cell's exterior and are a major component of plasma membranes, as they are bound to proteins (glycoproteins) or lipids (glycolipids) to form recognition sites. This recognition is crucial as it allows the immune system to differentiate between self and non-self entities, such as distinguishing body cells from foreign cells or tissues, which is essential for immune responses and preventing autoimmune reactions.