Question

the helium flash only occurs in low - mass stars because the extreme pressure in the star causes helium to undergo fission and break apart into hydrogen atoms the density and pressure of the degenerate matter in the helium core allows for runaway fusion of helium the helium gas in the interior of the star explodes outward and away from the star due to high pressure in the core the helium in the core is under very high pressure and gives off a burst of cosmic rays

Explanation:

In low - mass stars, the density and pressure of degenerate matter in the helium core enable runaway helium fusion, which is the helium flash. Helium does not undergo fission to break into hydrogen. The helium gas does not explode outward away from the star in the typical sense of an explosion, and it's not about giving off a burst of cosmic rays.

Answer:

the density and pressure of the degenerate matter in the helium core allows for runaway fusion of helium