Final answer:
The statement is true. The mass stays the same in a photosynthesis reaction due to the law of conservation of mass.
Step-by-step explanation:
The statement is true.
In a chemical reaction, the total mass of all the substances involved remains constant, which is known as the law of conservation of mass. This means that the mass of the reactants before the reaction is the same as the mass of the products after the reaction. So, in the case of the photosynthesis reaction, where the reactants are carbon dioxide and water, and the products are glucose and oxygen, the mass of carbon dioxide and water combined equals the mass of glucose and oxygen combined.
For example, consider the balanced equation for photosynthesis: 6CO2 + 6H2O -> C6H12O6 + 6O2. In this equation, you can see that the number of carbon atoms, hydrogen atoms, and oxygen atoms on both sides of the equation is the same. Therefore, the mass of the reactants before the reaction is equal to the mass of the products after the reaction, supporting the statement that the mass stays the same.