Answer:haemoglobin
Explanation:
Inside the air sacs, oxygen moves across paper-thin walls to tiny blood vessels called capillaries and into your blood. A protein called haemoglobin in the red blood cells then carries the oxygen around your body.
Answer:
D
Explanation:
Inheritance of genes from both parents
I may be wrong but, I would say the variable is the color of the light. At least that is what it sounds like to me.
