How do the lungs and heart transport oxygen in the cardio respiratory system

Which is not true about oxygen-17 and oxygen-18?

The combining of light nuclei is called blank. blank as in not actually blank. you know what im tryin to say.

An athlete is holding 24 lb of weights at a height of 6 inches above the stack as shown. to lower the weights, she applies a constant force of 5 lb to the handle. determine the velocity of the weights immediately before they hit the stack.