What type of herbicides are primarily root absorbed and translocated to leaves?

The correct answer is systemic herbicides. Systemic herbicides are specially designed to be absorbed by the plant's root system and then translocated throughout the plant, including to the leaves. This translocation allows systemic herbicides to control not only the parts of the plant that are immediately exposed to the herbicide but also the roots and other parts that might not come into direct contact with the chemical.

Systemic herbicides are particularly effective for targeting perennial weeds and deep-rooted plants because they can move through the plant and affect areas that may otherwise be beyond the reach of other herbicide types. This makes them a popular choice for managing tough weed problems where complete control is necessary.

In contrast, seedling growth inhibitors primarily affect the germination and growth of seedlings rather than being absorbed and translocated throughout the plant. Photosynthesis inhibitors disrupt the process of photosynthesis but are not necessarily absorbed by the roots to be moved to other parts of the plant. Contact herbicides, on the other hand, only affect the parts of the plant they come into direct contact with and do not provide the same internal efficacy as systemic herbicides.