Question

Which allowed scientists to determine that Earth was at least 4.3 billion years old?(1 point)
Responses

the electrical conductivity of uranium ions
the electrical conductivity of uranium ions

magnetic field surrounding zircon
magnetic field surrounding zircon

chemical reactivity of zircon ions
chemical reactivity of zircon ions

the radioactive decay of uranium to lead

Answer 1

The correct response is:

**the radioactive decay of uranium to lead.**

This method, known as uranium-lead dating, allows scientists to estimate the age of the Earth and obtain ages for the oldest rocks and minerals on the planet.

Answer 2

Question
Which evidence of the giant impact theory suggests that Earth and the moon may have once been in the same place?(1 point)
Responses

The composition of moon rocks and some Earth rocks are similar.
The composition of moon rocks and some Earth rocks are similar.

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

The amount of water on the moon and on Earth is similar.
The amount of water on the moon and on Earth is similar.

The temperatures on Earth and on the moon are similar.