Which type of cleavage results in cells whose future differentiation pathways are determined early?

Determinate cleavage refers to a type of developmental process where the fate of the embryonic cells is determined very early in development. In organisms exhibiting determinate cleavage, such as certain protostomes like mollusks and annelids, each cell's future role is predetermined as a result of the specific patterns of cell division. This means that if a cell is removed or damaged early on, it cannot compensate for that loss, as the development of that cell is already committed to a specific function or structure.

In contrast, indeterminate cleavage, typically found in deuterostomes such as mammals, allows for the cells to be more versatile, meaning that if one cell is lost, another can potentially take over its role because early cells retain the ability to differentiate into a range of cell types. Segmented and mosaic cleavage, while terms that describe specific patterns of cell division in other organisms, do not directly refer to the early determination of cell fate in the same way that determinate cleavage does. This clarity on how cell division affects differentiation is why determinate cleavage is the correct answer in this context.