Question

how does auxin affect the growth of plant stems? (1 point)
it builds up on the side of the stem that faces the light source and inhibits growth.
it builds up on the side of the stem that is away from the light source and stimulates growth.
it builds up on the side of the stem that is away from the light source and inhibits growth.
it builds on the side of the stem that faces the light source and stimulates growth.

Explanation:

Auxin accumulates on the stem side away from light, stimulating cell elongation and growth, causing phototropism.

Answer:

It builds up on the side of the stem that is away from the light source and stimulates growth.