Question

what is the medullary index of a hair if the medulla is 1 micron and the hair shaft is 3 microns?
0.5
3
0.75
0.3
hair is composed of a protein called keratin.
true
false
the cortex of the hair contains pigment (color).
false
true

Explanation:

Step1: Recall medullary index formula

The medullary index is calculated as the diameter of the medulla divided by the diameter of the hair shaft.

Step2: Perform the division

Given the medulla is 1 micron and the hair shaft is 3 microns, the medullary index = $\frac{1}{3}\approx0.33\approx0.3$.

For the second question, hair is composed of a protein called keratin, so it is True.

For the third question, the cortex of the hair contains pigment (color), so it is True.

Answer:

1. D. 0.3
2. True
3. True