It is a protein and it functions in a red blood cell to help carry oxygen
Ionic bonds result when electrons are tranfered between atoms. Covalent bonds result when valence electrons are shared between atoms. You should be able to identify whether an ionic or covalent bond is being formed between atoms.
Blood type doesn't fall into the category of dominant/recessive genes exactly; rather it combines this with the properties of incomplete dominance. Ignoring the Rh factor, there are 3 alleles for blood type, I^a,I^b, and i. You will be type A if you have I^a I^a or I^a i and type B if you have I^b I^b or I^b i. You can also get type AB by having the combination I^a I^b or be type O if you have i i. If you need to use dominant/recessive, you can say the A and B allele are dominant over the O allele and codominant with one another.