Question

which is one physical property that all stars have? they are made of gases. they shine very brightly. they have a triangle shape. they contain iron in their cores.

Explanation:

Stars are primarily composed of hydrogen and helium gases undergoing nuclear - fusion reactions. Not all stars shine very brightly (e.g., red dwarfs), stars are spherical in shape (not triangular), and not all stars have iron in their cores (iron is formed in the later stages of massive star evolution).

Answer:

A. They are made of gases.