Plz help solve idk probability

Find the greatest common factor of 28 and 35

Fractions can be added and subtracted only if they're fractions. a. like b. proper c. improper d. unlike

Iwill give brainliest only if your correct the words subsequent and submerge both contain the prefix sub. based on this information, what does the prefix sub most likely mean? a) under or secondary b) true or verifiable c) tricky or difficult d) around or centered on