I would say (C)because A you don’t need to test it because it may not be the same every time B it’s the same material for each boat so it gonna have the same mass and D you wouldn’t need to test each material because it each boat my not weigh the same cause of how much materials you use for each both because you can’t use the same exact material and measurements for each boat
The heart needs an abundant supply of blood to offer oxygen exchange for carbon dioxide and nutrition as well as take away waste products like carbon dioxide.