Gametic isolation occurs when which of the following is true?

Gametic isolation refers to a reproductive barrier that occurs when sperm from one species is unable to fertilize the eggs of another species, preventing interbreeding even if the organisms are physically capable of mating. This can happen for several reasons, including the chemical compatibility between the sperm and the egg.

In this context, the correct choice states that sperm cannot survive in the female reproductive system. This aligns with the concept of gametic isolation because if the sperm cannot persist or function adequately within the reproductive tract of another species, fertilization cannot occur. Therefore, this barrier effectively prevents the mixing of species' genetic materials.

The other options highlight conditions that either facilitate interbreeding or do not represent the obstacles posed by gametic isolation. For instance, if sperm can easily fertilize eggs of any species, that represents the opposite of isolation. The option about the egg having the correct chemical receptors suggests compatibility rather than isolation. Meanwhile, the choice regarding hybrid embryos developing into viable offspring pertains to hybrid viability rather than the initial gametic isolation process.