A. circle the portion of the molecule in model 1 that is polar. b. would this portion of the phospholipid mix well with water?

Attached is Model 1. I found the exercise on the internet.

A. The portion of the molecule that's polar is the head of the molecule - phosphorus containing group plus the glycerol backbone.
The other part of the molecule has two fatty acid chains which are hydrophobic meaning that they are nonpolar.

B. Yes, it would mix well with water because polar molecules are dissolved in water perfectly. Their partly positive portion and their negative polar connect to the positive charge of the H atoms and negative charge of the O atom of the water molecules.