The earth’s atmosphere contains about 0.04% (or 400 parts per million) carbon dioxide. although most of the carbon dioxide is in the form 12co2, which is not radioactive, a specific fraction of the total is made up of radioactive 14co2.
a) true
b) false

True

Explanation:

Yes the given statement is true

Most of the carbon dioxide preset in the atmosphere is C12 isotope and a very small fraction of The atmosphere is made up by C14 isotope which is radioactive in nature

C14 makes about 1 to 1.5 atoms per atoms of carbon in the atmosphere.

i believe it is-

d.) gravity pulled particles of dust and gas together to form planets.

16

explanation:

the marks go by 4s