Question

1. which molecule plays that largest role in plant phototropism?

proteins
chlorophyll
auxins
starches

Explanation:

• Proteins: Have various functions like enzymatic activity, structural support, etc., but not the main molecule for phototropism.
• Chlorophyll: Involved in photosynthesis (capturing light energy for making food), not phototropism (growth towards light).
• Auxins: Plant hormones. When light hits a plant, auxins redistribute. They accumulate on the shaded side, causing cells there to elongate more, making the plant bend (grow) towards the light - which is phototropism.
• Starches: Storage form of glucose in plants, not related to phototropism.

Answer:

auxins