B. Carbohydrates
The products of photosynthesis include glucose (a carbohydrate) and oxygen. :D hope this helps
Chemical energy is stored in the battery cells and converted to electrical energy when it's needed by the toy robot
The law of conservation of mass states that the mass will stay constant given a chemical reaction because no atoms were created or destroyed. This being said, an example can include water evaporating in a clear bottle outside on a hot day ( the mass of the bottle will stay the same, but the liquid water evaporated into gaseous water).