Final answer:
The student's dad would not have been eligible to vote in the 1970 election because the voting age was 21. The voting age was lowered to 18 in 1971 due to the activism of young people affected by the war in Vietnam.
Step-by-step explanation:
The student's dad would not have been eligible to vote in the 1970 election because the minimum voting age was 21. However, the voting age was lowered to 18 with the ratification of the Twenty-Sixth Amendment in 1971. This amendment was a result of the activism of young people, especially young men affected by the war in Vietnam who argued for their right to vote for the people in power who could send them to war.