How do the three experiments compare click on all the statements that are true about the comparisons

The number to the right of an element's symbol (ex. c-12) identifies the of an isotope.

Amixture with the same composition throughout is!

Inside a flashbulb, oxygen surrounds a thin coil of magnesium. when the flashbulb is set off, a chemical reaction takes place in which magnesium combines with oxygen to form magnesium oxide. which of the chemical equations matches the reaction above? a. mg + o2 mgo2 + energy b. 2mg + o mg2o + energy c. 2mg + o2 2mgo + energy d. mg + o mgo + energy