The mass number doesnt change, while the atomic number goes down by 1.
In electron absorption, a proton absorbs an electron to become a neutron.
In other words, electron absorption is the exact reverse of beta decay.
The man's body was recovered and pieces of tissue were studied for their C content by accelerator mass spectroscopy.
The best estimate from this dating technique says the man lived between 33 BC. From the ratio, the time since the formation of the rock can be calculated.
C and counting the amount of each) allows one to date the death of the once-living things.