Whats the mental equation that goes on in your head that explains equations

The sun a. will become a red giant within two to three million years b. is in its main sequence, which willlast thousands of years c. is in its main sequence, which will last billions of years. d. will explode as a supernova after its main sequence

Cigarette manufacturers purposefully add to cigarettes in order to give them a particular flavor. a. cocaine b. carcinogens c. cigarette ashes d. a and b

Which allows college students to work part time jobs to pay for educational expenses