Final answer:
A generation spans approximately 30 years, and since the year 0 AD, about 67 generations have passed as of 2023 AD.
Step-by-step explanation:
A generation is typically considered to be about 30 years, which is approximately one-third of a lifetime. Since the year 0 AD, approximately 67 generations have passed, assuming we are currently in the year 2023 AD. This calculation is based on the estimation that there are about 30 years in a generation; hence, the math would be 2023 divided by 30, which equates to about 67.43, rounded down to 67 generations.