Humber Admissions Practice Test 2026 - Free Practice Questions and Study Guide for Humber College Admissions

The correct answer focuses on carbohydrates, particularly their role in cell communication. Carbohydrates are often found on cell surfaces as glycoproteins or glycolipids, where they serve as recognition sites that allow cells to interact with each other. These carbohydrate structures facilitate cell recognition and signal transduction, playing a key role in various biological processes including immune response and tissue formation.

In contrast, while proteins also play vital roles in cell communication, they primarily function as receptors or signaling molecules rather than being directly involved in the identification and interaction that carbohydrates provide. Phospholipids mainly contribute to membrane structure and fluidity but do not directly participate in communication between cells. Cholesterol contributes to membrane stability and fluidity but lacks a direct role in cell-to-cell communication, making carbohydrates the primary component for this function.