wrinkle in time

I asked befor but I have bunch of question, I cant understand because My english is not good, so I have 4 question

1.What was Mrs. Murry removing that caused Mrs. Whatsit to fall and make a mess?

2.Why did the principle send for and speak to Meg?

3. What happend to them that made it seem that everything disappeard and then came back?

4.what did Mrs. Whatsit turn into?