The following statements describes properties of stars;
Stars produce energy through nuclear fusion.
Stars are massive objects composed of gas.
Stars are composed primarily of hydrogen and helium
Explanation:
Stars mainly burn hydrogen gas in their core by fusion to produce the enormous energy they produce. Due to the immense gravity form their mass, stars are able to compress hydrogen gas in their core such that the atoms of the gas fuse to form heavier elements like helium. In the process, high energy is released such as in the form of electromagnetic radiation and neutrons. If the star is even bigger (supermassive stars), they are able to fuse helium into carbon dioxide producing even more fusion energy. Therefore, starts are mainly enormous blobs of burning gases.