Which sequence shows the early life cycle of a star?

Which sequence shows the early life cycle of a star?

• A. Nebula → Protostar → Adult star
• B. Protostar → Nebula → Adult star
• C. Nebula → Adult star → Protostar
• D. Star → Nebula → Protostar

Answer: (A)

Stars form from a cloud of gas and dust called a nebula. As gravity pulls the cloud inward, a protostar forms and heats up as material continues to accrete. When nuclear fusion begins, the object becomes a mature, shining star. So the early-life sequence must move from Nebula to Protostar to a main-stage, or “adult,” star. The option that follows this order is Nebula → Protostar → Adult star. The other sequences either reverse steps or skip the protostar stage, which isn’t how star formation unfolds.

Stars form from a cloud of gas and dust called a nebula. As gravity pulls the cloud inward, a protostar forms and heats up as material continues to accrete. When nuclear fusion begins, the object becomes a mature, shining star. So the early-life sequence must move from Nebula to Protostar to a main-stage, or “adult,” star. The option that follows this order is Nebula → Protostar → Adult star. The other sequences either reverse steps or skip the protostar stage, which isn’t how star formation unfolds.