The average hair density on the human scalp is about how many hairs per square inch?

Step 3: Recall or research the typical range of hair density on the human scalp. Hair density varies among individuals, but the average is generally within a specific range that can be compared to the options provided.

Step 4: Eliminate options that are either too high or too low based on biological knowledge. For example, 10,000 hairs per square inch is excessively high and unlikely, while 100 hairs per square inch is too low for average density.