Question

q7. to move to the roots of a plant, a sugar molecule must exit the cell where it was produced and enter the stream of plant fluid that carries sugar to other parts of the plant (known as phloem). a newly created sugar molecule is transported to the phloem through diffusion. this means that sugar molecules:
move randomly within the cell until, by chance, they exit the cell and enter the phloem.
travel away from the cell organelle where they are produced (chloroplast), until they enter the phloem.
travel away from areas of high sugar concentration, such as the chloroplast, until they enter the phloem.
move randomly until they encounter the phloem, and then stop moving as they are carried along by the phloem.

Explanation:

Diffusion is the movement of particles from high to low concentration, randomly. Chloroplast (sugar production) has high sugar concentration. So sugar moves away from high - concentration chloroplast (due to random motion and concentration gradient) to phloem (lower concentration). Option 1: Random movement until exiting (matches diffusion's randomness). Option 2: "travel away" implies directed, not random. Option 3: "travel away" is not random. Option 4: Molecules don't stop moving in phloem. So the correct option is the first one.

Answer:

Move randomly within the cell until, by chance, they exit the cell and enter the phloem.