How is trace collected?

Which of these provides the most highly magnified image?

How many times can an SEM magnify an image?

This structure is contains the melanin in human hair

This is the color pigment in human hair (and skin)

This fiber is flat in shape and folds or twists on itself

This fiber is made of purified cellulose

This is the thinnest natural fiber

This structure is often small or even absent in humans

This transparent structure often appears scaly on the surface

Which fiber is shown here?

Which fiber is shown here?

The medulla of a hair found at a crime scene is 40 µm in diameter. The diameter of the hair shaft is 100 µm. What is the medullary index and is it human?

Trace amounts of marijuana are found in a hair at 6.0 mm from the root. How many days ago was this person exposed to marijuana? Assume hair grows at 0.5 mm/day.