Question

He has black hairs? correct sentence​

Answer 1

He has black hairs. (Incorrect)

He has black hair. (Correct)

• The given statement is incorrect because 'hairs' is not a grammatically correct term.
• Always, we need to use the singular form for hair.
• Another such example is that of 'teeth' It is a plural term in itself.  
• One must keep in mind these exceptions without which the sentence framing would not be proper.