In the night sky, stars often look like a multitude of bright lights barely distinguishable from one another. But the fact is that stars vary greatly. The differences are difficult to see from far away. Can you guess the ways in which stars differ from one another? And what do they have in common?

The correct answer is -

differences: color, brightness, temperature, size, and mass

similarities: They are balls of gas, mostly hydrogen and helium

Explanation:

Stars look mostly the same from anywhere or any place and tough to differentiate or distinguish one from another. Star can be different on the various ground even they look similar from far away.

Stars can be of various colors from red to blue and brightness can be different as well, color depends on temperature, and brightness depends on the size of the star.

Stars are grouped by the size that ranges from dwarf to supergiant. The temperature of the stars also varies which affects the color and brightness as well.  

Stars are the big balls of gases composed of mainly helium and hydrogen all are always under a nuclear reaction.

answer; /// the correct )

the missing space is phylum