What phase of a human life does not have a definite starting point?
childhood
adolescence
death
adulthood
Adulthood does not have a definite starting point. A person may be physically mature by age 16 or 17 but not defined as an adult by law until older ages. In the U. S. , you can’t join the armed forces or vote until age 18. You can’t buy or use alcohol or take on many legal and financial responsibilities until age 21.