Which allowed scientists to determine that Earth was at least 4.3 billion years old? (1 point)
O chemical reactivity of zircon ions
O the electrical conductivity of uranium ions
O magnetic field surrounding zircon
O the radioactive decay of uranium to lead
O the radioactive decay of uranium to lead
Which evidence of the giant impact theory suggests that Earth and the moon may have once been in the same
place? (1 point)
O
The type of gases in the atmospheres of Earth and the moon is the same.
O
The temperatures on Earth and on the moon are similar.
O
The composition of moon rocks and some Earth rocks are similar.
O The amount of water on the moon and on Earth is similar.
O The composition of moon rocks and some Earth rocks are similar.
How long ago do scientists think the solar system formed? (1 point)
O 6.2 billion years ago
O 4.3 million years ago
O 2.6 billion years ago
O 4.6 billion years ago
O 4.6 billion years ago
Why is deuterium oxide called "heavy water"? (1 point)
O It has extra hydrogen atoms.
O Its oxygen atoms are heavier than others.
O It has extra oxygen atoms.
O Its hydrogen atoms are heavier than others.
O Its hydrogen atoms are heavier than others.
Why is it hard to find the age of Earth? (1 point)
O The Earth is constantly moving.
O There are too many layers of Earth.
O Earth's surface is constantly changing.
O There is no way to find the age of rocks.