1.   At local drug stores, the only kit available tests hair strands, which generally are not considered as accurate as urine tests.

2.   The heat causes the liquid to harden, and it melts the wax, adhesive and any organic material inside while leaving an impression of the hair strands.

3.   The teachers joked as they studied their hair strands.

4.   Genetic testing studies human cells left at a crime scene in blood stains and hair strands.

5.   They appeared interested when charts of hair strands were displayed.