Which option is a compound?
carbon
O carbon dioxide
O air
O oxygen

Carbon dioxide is a compound.

Explanation:

Carbon is the sixth element in the periodic table. Located between boron (B) and nitrogen (N), it is a very stable element. Because it is stable, it can be found both by itself and in many naturally occurring compounds. Scientists describe the three states of carbon as diamond, amorphous, and graphite.

Carbon dioxide (CO2 ) is a chemical compound composed two oxygen atoms covalentl bonded to a single carbon atom. Carbon dioxide: Carbon dioxide is a molecule composed of one carbon atom bonded to two oxygen atoms via two double bonds.

Air is mixture, but not a compound because of the following reasons: Air can be separated into its constituents such as oxygen, nitrogen, etc. by fractional distillation of liquid air. Air shows the properties of all gases present in it.

Oxygen in the atmosphere is a molecule because it contains molecular bonds. It is not a compound because it is made from atoms of only one element - oxygen. This type of molecule is called a diatomic molecule, a molecule made from two atoms of the same type.

i believe it is-

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