Answer:
1. Completing these questions instead of doing something else
Benefits:
Getting a good grade.
Getting a dopamine rush from completing a task.
Learning a few more things about the topic.
Learning a few more things about yourself.
Costs:
Time spent doing the task.
Brainpower (calories) used to complete the task.
Not doing something else, either more enjoyable for you, or more productive (opportunity cost).
2. Getting a job after high school instead of going to college
Benefits:
obtaning income immediately after graduating
Perhaps being able to become independent from your parents
getting work experience
Perhaps starting a career in some industry
Costs:
The average college-graduate earns more than the non-college graduate, so getting a job instead of going to college may represent a huge opportunity cost in terms of income later on
Losing the opportunity of engaging in academic life
Losting the opportunity of getting high skilled jobs in the future (most of them require college degrees).
3. Going straight from high school into college
Beneftis
Engaging in academic and social life in a new setting
Learning many new things that perhaps otherwise would not be learnt
Having the opportunity to meet good professors and classmates
Costs
You will likely be unable to hold a full time job
Giving up on the opportunity to earn an income, get job experience
Probably going into debt