Unless extraterrestrial humans enter Earth or people leave to inhabit another planet, net global immigration and emigration are both zero. Thus, to reduce the rate of global population change, the number of births must be reduced or the number of deaths must be increased.
Measure the amount of certain radioactive elements in the rock when rocks are formed, small amounts of radioactive elements usually get included as the rock ages, more and more of the uranium changes into lead.
My dad if this doesn’t help