Why is it important to center the object you are observing in your field of view before switching to a higher power?

i think that d. wind is the answer.   i missed the question when i answered a. currents.

1. b.

2. d.

3. a.

5. d.

6. c.

these are the only ones that i know, i hope this , and good luck.

the contamination

we are putting to many trash.

i think its both a and b