Question

during the life cycles of stars, hydrogen and helium are converted into heavier elements such as carbon and oxygen. which of the following types of reactions causes these conversions?
a convection
b. fusion
c. fission
d. nebular

Explanation:

To determine the reaction converting hydrogen and helium to heavier elements in stars, we analyze each option:

• Option A (Convection): Involves heat transfer (fluid movement), not element creation.
• Option B (Fusion): Nuclear fusion in stars fuses lighter nuclei (e.g., H, He) into heavier elements (e.g., C, O) by combining atomic nuclei.
• Option C (Fission): Splits heavy nuclei into lighter ones (opposite of star reactions).
• Option D (Nebular): Refers to nebula formation (star birth), not element conversion.

Fusion matches the process of creating heavier elements from lighter ones in stellar cores.

Answer:

B. fusion