you see katie helped sandra with homework, which helped sandra not fail. Because katie did not let sandra fail, sandra can graudate and get a job. She can also thank katie for not letting sandra fail and go homeless.
sandra helped katie rollerblade. which has no significant impact. Who cares about rollerblading.
your answer is C
Dissolution
Oxidation
Carbonation
Hydrolysis
Boys need 2,400 to 3,200 a day, while girls need 1,800 to 2,400 a day.
Hope this helps!