how long ago do scientists think the solar system formed?(1 point)
6.2 billion years ago.
2.6 billion years ago.
4.3 million years ago.
4.6 billion years ago.
Scientists believe that the solar system formed approximately 4.6 billion years ago.
Which allowed scientists to determine that earth was at least 4.3 billion years old? (1 point)
Chemical reactivity of zircons ions
Magnetic field surrounding zircon
The radioactive decay of uranium to lead
The electrical conductivity of uranium ions
The radioactive decay of uranium to lead allowed scientists to determine that Earth is at least 4.3 billion years old.
Why is deuterium oxide called "heavy water"? (1 point)
It's oxygen atoms are heavier than others.
It has extra hydrogen atoms.
It has extra oxygen atoms.
It's hydrogen atoms are heavier than others.