It is A because the diagram for choice A shows correctly how cellular respiration produces energy and releases carbon dioxide and water as byproducts(CO2). And it also shows how photosynthesis release or produces oxygen gas (O2)
THE blood group AB is called the universal receiver because any other blood group can be compatible with this blood group this is due to the absence of anti-bodies in this type
while blood group O is called the universal donor because it is compatible with all blood groups due to the absence of antigen (A and B)
while blood group A receives blood from itself and O and donates blood to itself and AB thesamethinggoeswithbloodgroupB