This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Hematopoeisis: Basic concepts, Subject name: Pathology
Ratio of fat cells and blood cells in bone marrow is- 
Select and explain. 
A. 1:04, B. 1:02, C. 1:01, D. 2:01
C: 1:01
Answer: C: 1:01 
Explanation: Ratio of fat cells and blood cells in bone marrow is 1:1 Normal Myeloid: Erythroid ratio = 3-4:1. Normal ratio of marrow cells: fat cells=1:1. Normal Cellularity (%) = 100 - Age. Decreases with age At 10yrs =100-10=90% cellularity At 30yrs=100-30=70% cellularity