Question

1. nebulae are also called \the birthplace of stars.\ explain why they have that name.

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Explanation:

Nebulae are dense clouds of gas (mostly hydrogen and helium) and dust in space. Gravity causes clumps of this material to collapse in on themselves; as these clumps shrink, they heat up and increase in pressure. When the core temperature and pressure reach a threshold where nuclear fusion can begin, a new star is formed. This process of star formation originates entirely within the structure of nebulae, giving them the nickname "the birthplace of stars."

Answer:

Nebulae are called "the birthplace of stars" because they are dense clouds of gas and dust where the process of star formation occurs: gravitational collapse of clumps of this material creates high enough core temperature and pressure to ignite nuclear fusion, forming new stars.