(1) All the genotypes are as follows: AABB, AaBB, AABb, AaBb, aaBB, aaBb, AAbb, Aabb, aabb.
(2) Assuming that Aa is dominant and Bb is recessive, there will be 9 phenotypes with both A and B allele dominant (i.e. AaBb, AABb); there will be 3 phenotypes with just the A allele dominant (i.e. Aabb, AAbb); there will be 3 phenotypes with just the B allele dominant (i.e. aaBb, aaBB); and there will be 1 phenotype with both alleles recessive (i.e. aabb). The phenotypic ratio in this case is 9:3:3:1.
(3) The probability of producing an offspring with the aabb genotype is 1/16 or 6%.
Carbon Dioxide (or CO2) is produced by the lungs I think because when you inhale, you breathe in oxygen, then you exhale the carbon dioxide in the lungs. That's actually 3 and 4. As for number 2, I want to say either the alvioli or however that's spelled but technically, the entire body uses oxygen so I'm not sure.
Your answer is B.) Heterozygous, since the prefix 'hetero' usually means separate or different. Hope this helps.