Enzymes and plasmids
Your estimation of the sizes of the fragments for pC508 are incorrect. 

Look at the size of the plasmid at the center of the circle.The size of your fragments has to add up to that number. So if you were sure that one fragment was 1000bp, then the other fragment would need to be 6300bp.

You should also notice that fragment sizes for EcoR1 and HindIII digests should not be the same size.

You also need to say something about the type of DNA you have in the pBR322 lanes. Is it linear, circular, supercoiled?

For question 2, your explanation for pBR322 is okay, you should still mention the type of DNA you have in those lanes.

You need to explain not only where PSTI cut but also the size of the fragments that it produces.

A place where a restriction enzyme cuts is called the restrictions site, so instead of saying cuts in one place, or two places, you should say at a single restriction site, etc.