receive in a transfusion? Explain. 3. Explain why Rh incompatibility is a problem only when a foetus is Rh-positive, and the mother is Rh-negative but not vice-versa. 4. Describe, in detail, the pathway of an oxygen molecule as it moves from the air outside your body, into your blood, and to a cell in a muscle in your arm. You could write your answer in words, or use a flow diagram, or perhaps a mixture of both. You will need to think about what you have learnt about the human transport system, as well as what you have learnt in human respiratory system chapter. 5. Explain why maize grain is called as a fruit and not a seed?