This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
Abnormal increase in the number of RBCs is known as: 
Select and explain. 
A. Leukocytosis, B. Polycythemia, C. Anaemia, D. Thrombocytosis
B: Polycythemia
Answer: B: Polycythemia 
Explanation: Abnormal increase in the number of RBC is known as Polycythemia.
In severe polycythemia (excessive production of red blood cells), the increase in resistance does increase the work of the heart. 
Reference: Ganong’s Review of Medical Physiology T W E N T Y - F I F T H   E D I T I O N page no 574