Yes they are.
Some types of seafood contain little mercury. The Food and Drug Administration (FDA) and the Environmental Protection Agency (EPA) say pregnant women can safely eat up to 12 ounces a week (340 grams)...
Yes. Melon's a great thing to eat during pregnancy because it's full of water and so will keep you hydrated
No, it can kill the baby.
Would depend on what's on the pizza(type of cheese etc) but basically yes.