Please also give some explaination for the answer.

1.1) What is the "phase problem" in X-ray crystallography? 1.2) List 2 chemical variables that can be optimized for crystallization. 1.3) List 2 physical variables that can be optimized for crystallization. 1.4) A crystal has space group F41 32. How many lattice points does its unit cell contain? 1.5) A crystal has space group P4321 2. What symmetry elements are present