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: Social & Preventive Medicine
Trace element is what percent of body weight 
Select and explain. 
A. 0.01%, B. 0.00%, C. 0.10%, D. 1%
A: 0.01%
Answer: A: 0.01% 
Explanation: None