Question

Four billion years from now, the Sun's core will consist mostly of:

A) hydrogen
B) helium
C) carbon
D) silicon
E) iron

Answer 1

In four billion years, the core of the Sun will mostly consist of helium, as it transitions from fusing hydrogen into helium to fusing helium into heavier elements.

Step-by-step explanation:

The Sun, like other stars, goes through several stages in its life cycle. Initially, it is powered by the fusion of hydrogen into helium. As the Sun grows older and exhausts its hydrogen supply, it will start to fuse helium into heavier elements such as carbon and oxygen. Four billion years from now, the Sun's core will mostly consist of helium. After the helium is depleted, it may start to fuse carbon into heavier elements, but it will not reach the stage where it will have a core of iron. That stage is reserved for much more massive stars that eventually undergo a supernova.