Nebula is a cloud in deep space consisting of gas or dirt/dust (e.g. cloud formed after a star explodes). Protostar is the earliest stage of a star. It is before the nucleosynthesis has set in motion.

Is nebula a protostar?

How is a Protostar Formed? Inside a nebula, there are areas where gravity causes dust and gas to “clump” together. As these “clumps” gather more and more mass their gravitational pull increases, forcing more atoms together. This process is known as accretion, and the result is a protostar.

How are nebulae and protostars alike?

is that nebula is (astronomy) a cloud in outer space consisting of gas or dust (eg a cloud formed after a star explodes) while protostar is (star) a collection of gas and dust in space with high temperature that usually grows to the point of beginning nuclear fusion and becoming a star.