Answer: A)Atoms begin to gravitate together to form a center.
Explanation:
A nebula is a stellar nursery where stars are born. A nebula is a cloud of dust and gases. The disk starts swirling and atoms begin to gravitate and come together. A center is formed. This center forms the core. When enough mass is gathered to generate accurate temperature and pressure, nuclear fusion reaction kicks in to produce heat and light and a star is born.
