Questions

The trajectory of the bullet is a parabola

STARTLING is a required 9 letter English word is still a word each time you remove a letter from the word. And how it is shown below: 

1. Remove the L, and the word becomes: STARTING

2. Remove one T, and the word becomes: STARING

3. Remove the A, and the word becomes: STRING

4. Remove the R, and the word becomes: STING

5. Remove the other T, and the word becomes: SING

6. Remove the G, and the word becomes: SIN

7. Remove the S, and the word becomes: IN

8. Remove the N, and the word becomes: I

Yes, a promise can be broken without being held.

A typical giraffe neck can stretch as long as six feet, the giraffe's tongue usually measures 18-20 inches long.

Why that much long:

Giraffe's eat Acacia tree leaves. The acacia tree's tasty leaves are protected by very sharp thorns. The giraffe's long tongue allows it to reach the highest, tastiest leaves while avoiding the sharp thorns. Its tongue also features a thick, tough layer that protects it from being cut by the thorns. If a giraffe's tongue does get cut by a thorn, its extra-thick saliva has antiseptic properties that help it to heal quickly.