1. Why is there more carbon-14 in living bones than in once-living ancient bones of the same mass? 2. Why is lead found in all deposits of uranium ores? 3. How does the mass of a pair of atoms that...

1. Why is there more carbon-14 in living bones than in once-living ancient bones of the same mass?

2. Why is lead found in all deposits of uranium ores?

3. How does the mass of a pair of atoms that have fused compare to the sum of their masses before fusion?