The answer to this is : B, Their roots.
The difference between the two students that we know of is that they used a different meter stick. So the difference would be best attributed to the different tools they used.
Note, this is quite a huge difference. It's likely that one of the sticks, or both, are quite defect.
Answer: melanin
Explanation: Further, other cells contribute to the function of the epidermis. Melanocytes are cells that produce melanin, a compound involved in skin pigmentation produced in response to ultraviolet (UV) light exposure (6). Melanin can absorb energy from UV light to shield underlying tissues from damage.
