Which one of the following statements is not a correct statement of the law of conservation of mass?
a) the mass of a system is conserved in a chemical reaction.
b) the mass cannot be created or destroyed by chemical reactions.
c) the mass of a system is dependent upon chemical reactions that may occur.
d) atoms are conserved in chemical reactions.

c) The mass of a system is dependent upon chemical reactions that may occur.

Explanation:

Law of Conservation of Mass -

Also called the principle of mass conservation , this law was first independently given by the scientist Mikhail Lomonosov and later was rediscovered in 18th century by the father of chemistry Antoine Lavoisier .

According to this law , for a closed system , the mass of the system remains constant , before and after a reaction .

Therefore , the mass is conserved for a chemical reaction .

The statement a , b , d are completely correct ,

But the incorrect statement is the c , because the mass of the system is independent of the chemical reaction .

i don't see a text, but i am gonna assume this *orbit* the curved path, usually elliptical, described by a planet, satellite, spaceship, etc., around a celestial body, as the sun.