Answer:
a. 1/2 b. The organism is an animal
Step-by-step explanation:
a. What is the medullary index for an organism that has a medulla width of 2cm and hair shaft width 4cm?
Medullary index = diameter of medulla/diameter of hair.
Given that diameter of medulla = medulla width = 2cm and diameter of hair = hair shaft width = 4cm,
Medullary index = diameter of medulla/diameter of hair = 2 cm/4cm = 1/2
b. Is this organism human or animal?
Since the medullary index = 1/2 > 1/3 (if it is ≤ 1/3 it is human hair and ≥ 1/2 it is animal hair), it is animal hair. So, the organism is an animal.