In embryology, the terms “prospective potency” and “prospective fate” describe critical concepts that explain how embryonic cells develop into various tissue types. In regulative development, understanding the relationship between these concepts is key to appreciating developmental flexibility.

Prospective potency refers to the range of possible cell types a specific embryonic cell can potentially become given the right conditions. In contrast, prospective fate is the actual cell type the cell will develop into under normal developmental circumstances.

In regulative development, which is typical of vertebrates, cells retain a high degree of flexibility and responsiveness to their environment. This allows cells to adjust and compensate if their surroundings change. Due to this plasticity, the prospective potency of cells in regulative development is generally greater than their prospective fate. In other words, cells can potentially become multiple different cell types, but under normal development, they adopt a specific fate.

This is different from mosaic development, where cell potency typically equals prospective fate because cells are already determined early and have restricted developmental potentials.

Experimental evidence supporting this idea comes from embryonic manipulations where cells can change fate when repositioned or if parts of the embryo are removed. Such adaptability showcases that cells in regulative development are conditionally specified and retain broader potency.

In summary, for regulative development:

• The prospective potency of cells is more than the prospective fate.

• Cells have the potential to adopt multiple fates depending on environmental or positional cues.

• This flexibility underpins the regulative and compensatory abilities of embryos.

Therefore, in answer to the question, the correct choice is:

(2) More than prospective fate