Question

the helium flash only occurs in because protostars binary stars high - mass stars low - mass stars

Explanation:

The helium - flash occurs when a star runs out of hydrogen in its core and starts to fuse helium. In low - mass stars, the core is degenerate before helium fusion begins. When the temperature rises high enough for helium to fuse, it occurs explosively in a helium flash. This does not happen in protostars (which are still in the process of forming), binary stars (this is a classification based on the number of stars in a system and not directly related to the occurrence of helium flash), or high - mass stars (which have different core conditions and do not experience a helium flash in the same way).

Answer:

low - mass stars