The medulla, pons, and the cerebellum are three main parts of the hindbrain.
Brain is the centre of the nervous system. It is enclosed in the skull cranium. The primary regions of the brain are the forebrain, midbrain and the hindbrain. The forebrain consists of the cerebrum and diencephalon. The midbrain is a small tubular region between the forebrain and the hindbrain. The hindbrain is made up of the medulla oblongata, pons and cerebellum.
Cerebellum is the second largest portion of the brain which helps in maintaining the body's equillibrium, coordinates muscular movements and body posture. Pons is the structure located in the brain stem which relays impulses from medulla to cerebellum and vice versa. Medulla oblongata is the lowest part of the brain stem controlling involuntary reflexes and has the respiratory and cardiac centres in it controlling respiration and heart beats respectively.
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.
Near the surface or the shallow water. Hope I helped
