If new stars form as a result of exploding stars compressing nebulae, then how did the first stars form if there were no stars to compress the gases

the size of a nebula is what compresses the gases in space.

a nebula is slowly rotating and the gases, and other space dust, and minerals are slowly moving closer to the center of the nebula.(because of gravity) A star forms when a colossal amount of hydrogen, helium, carbon, oxygen and other trace minerals are all attempting to occupy a very small area in space. this causes those elements to super-heat which creates stars. stars that go supernova usually cause nebulae to collapse faster by causing a wave of distorted gravity(which causes the elements to be moved in one direction faster than if a nebula formed a star normally).

the dna of humans and mice is almost 92% similar. this similarity indicates that . mice have a tail, while humans have a tailbone. the tailbone is a structure in humans.yes it's true.

the most common type of reef is the fringing reef. this type of reef grows seaward directly from the shore. they form borders along the shoreline and surrounding islands.