Which allowed scientists to determine that Earth was at least 4.3 billion years old?

Question

Responses

magnetic field surrounding zircon
magnetic field surrounding zircon - no response given

the radioactive decay of uranium to lead
the radioactive decay of uranium to lead - no response given

chemical reactivity of zircon ions
chemical reactivity of zircon ions - no response given

the electrical conductivity of uranium ions

Answer 1

the electrical conductivity of uranium ions - no response given

Answer 2

Which evidence of the giant impact theory suggests that Earth and the moon may have once been in the same place?
Responses

The composition of moon rocks and some Earth rocks are similar.
The composition of moon rocks and some Earth rocks are similar. - no response given

The amount of water on the moon and on Earth is similar.
The amount of water on the moon and on Earth is similar. - no response given

The temperatures on Earth and on the moon are similar.
The temperatures on Earth and on the moon are similar. - no response given

The type of gases in the atmospheres of Earth and the moon is the same.

Answer 3

The type of gases in the atmospheres of Earth and the moon is the same. - no response given

Answer 4

How long ago do scientists think the solar system formed?
Responses

2.6 billion years ago
2.6 billion years ago - no response given

6.2 billion years ago
6.2 billion years ago - no response given

4.6 billion years ago
4.6 billion years ago - no response given

4.3 million years ago

Answer 5

4.6 billion years ago - no response given