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

It is very hard to catch breathe when you run fast.

Demoiselles

These are rock pillars which stand as resistant rocks above soft rocks as a result of differential erosion of hard and soft rocks.

Zeugen

A table-shaped area of rock found in arid and semi-arid areas formed when more resistant rock is reduced at a slower rate than softer rocks around it.

A Dreikanter

It is a type of ventifact that typically forms in desert or periglacial environments due to the abrasive action of blowing sand.

A wind gap is a gap through which a waterway once flowed that is now dry as a result of stream capture.