Question

what is the function of the epithelium?
a) take up nutrients by passive and active transportation
b) building an impermeable barrier for food - borne pathogens
c) build a barrier that only allows certain substances to pass through
d) all answers are correct.

Explanation:

• Epithelial cells use passive (e.g., diffusion) and active transport to absorb nutrients, so option a is correct.
• Epithelial layers form a physical barrier that blocks most food-borne pathogens, making option b correct.
• Epithelia are selectively permeable, meaning they only let specific substances pass, so option c is correct.

Since all individual statements are valid, the combined option applies.

Answer:

d) All answers are correct.