What do pigment inhibitors prevent plants from forming?

Pigment inhibitors are a class of herbicides that specifically target the biosynthesis of pigments in plants, most notably chlorophyll. Chlorophyll is the green pigment that is essential for photosynthesis, the process by which plants convert sunlight into energy. When pigment inhibitors are applied, they interfere with the pathways that plants use to produce chlorophyll, ultimately preventing its formation. This lack of chlorophyll results in a loss of green coloration in the plant, leading to stunted growth and, in severe cases, plant death due to the inability to perform photosynthesis effectively.

In the context of the other options, water, roots, and flowers are not directly affected by pigment inhibitors. While plant growth may be impacted due to the lack of chlorophyll, these processes do not primarily involve the inhibition of pigment production. Therefore, the most precise answer to the question about what pigment inhibitors prevent plants from forming is chlorophyll.