This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General physiology, Subject name: Physiology
Fast fatigable motor unit are recruited 
Select and explain. 
A. First, B. Last, C. During active pa of contraction, D. During relaxation
B: Last
Answer: B: Last 
Explanation: White muscle fibers are the fast fatigable motor units and are recruited last Red muscle fibers are rich in mitochondria and hence don't get fatigue soon Ref:Guyton and Hall textbook of medical physiology 12th edition,page number:91,92,93