Question

q6. plants use sunlight to produce sugar molecules in their leaves. some of this sugar is needed by cells in the roots. would you expect plants to rely on diffusion to transport the sugar molecules from leaves to roots, and why?
yes, because diffusion will happen naturally, so the plant does not have to spend energy on it.
yes, because all materials in living tissues move by diffusion.
no, because it would take too long for the sugar molecules to diffuse that far.
no, because diffusion only operates over small distances, not over long distances.

Explanation:

Diffusion is effective over short distances (e.g., within cells or between adjacent cells). Transporting sugar from leaves to roots (long - distance) via diffusion is impractical as it would be extremely slow. The first two options are wrong as diffusion isn't suitable for long - distance transport in plants. The third option says it would take too long, but the key reason is that diffusion is for short distances, so the fourth option is correct.

Answer:

D. No, because diffusion only operates over small distances, not over long distances.