The doctors would be able to give Type A, Type B, Type O and Type AB
Dorsal means back as in the back area. Example~ Many dolphins have a pronounced beak and all have a central dorsal fin and sharp teeth for feeding, mainly on squid and fish.
Active deffusion.. this way the water is retained and the unnecessary salts ions are expelled out.
Any physical characteristic can be passed on from generation to generation. However, some characteristics are influenced by the environment as well as having a genetic predisposition for that specific trait.
I believe (B) is the best option due that it mentions the reason causing natural selection with limited supplies competition increases making it more likely for the strongest individuals to survive
