I need help with AP Bio questions on DNA?

I can't find the answers to these questions! And some I am unsure of...

1. Most molecules with regular structure produce specific _________ diffraction pictures.

I guessed and put "x-ray". Is it right?

2. When nucleotides are linked together in DNA, the __________ group attached to the 5' carbon of one sugar attaches to the 3' carbon of an adjacent sugar.

Is it phosphate? Or what?

3. Recombinant DNA may make it possible to produce ________ protein in _______ cells.

4. T or F: All members of the same species of organism contain DNA with almost exactly the same chemical composition.

5. Restriction enzymes attack double stranded DNA:

A) only at the 3' end

B) only at the 5' end

C) at a point in the middle of a particular nucleotide sequence

D) only between cytosine and guanine containing nucleotides

Thanks for the help. I've tried searching around and reading through my notes and handouts, but I can't find the answers.