D. The total number of atoms when glucose and oxygen react stays the same when carbon dioxide and water are produced. The conservation of the mass is a fundamental law of chemistry and physics. It indicates not only that during any experiment, including if it involves a chemical transformation, the mass is conserved, but also that the number of elements of each chemical species is conserved. Like any law of conservation it is expressed by a conservation equation.
It took mark 2 hours to ride his bike to his grandma's house, which was 12 miles away. I divided 2 by 12 and got 6. Remember this: mph = miles away ÷ time.
