Question

The table below lists four pathways that happen during various stages of the life cycles of stars in the universe. The table shows which atoms are present before fusion, and which atoms are present after fusion.





Pathways in Stars
Pathway # Atom Conversions That Occur
1 Si → Fe + Ni
2 He → C + O
3 Ne → O + Mg
4 H → He








Which pathway(s) occur on the sun?




3 only


4 only


2 and 4


1 and 3

Answer 1

2 and 4

Explanation: The Sun currently fuses hydrogen into helium (pathway 4). Later, in its red‑giant/helium‑burning phase it will fuse helium into carbon and oxygen (pathway 2). Neon and silicon burning (pathways 3 and 1) occur only in much more massive stars.