In a leaf photosynthesis experiment, which portion of the leaf would show no starch after being covered for 4 hours?

In a photosynthesis experiment, the production of starch in leaves can be used as an indicator of photosynthetic activity. Starch is produced when chlorophyll-containing parts of the leaf absorb light and convert carbon dioxide and water into glucose, which is then stored as starch.

Leaves have areas that contain chlorophyll (typically the green parts) and areas that do not (such as those covered with opaque materials). If any portion of a leaf is covered and deprived of light, that area will not be able to perform photosynthesis effectively, leading to no starch production.

Given that the question asks which portion of the leaf would show no starch after being covered for 4 hours, any covered area, regardless of the color of the covering, would not be able to photosynthesize. A covered portion will not receive the light necessary for photosynthesis, causing it to lack starch accumulation. Thus, any of the covered portions would exhibit this characteristic, reflecting the general principle that photosynthesis requires light.