Final answer:
Pastoralists in Africa who use French milk have a higher proportion of lactose tolerance compared to those who use fermented milk products due to a genetic mutation that allows lactose tolerance.
Step-by-step explanation:
The higher proportion of lactose tolerance among pastoralists in Africa who use French milk compared to those who use fermented milk products can be attributed to the genetic mutation that allows lactose tolerance. Lactase, an enzyme that metabolizes lactose, is produced in individuals who are lactose tolerant, enabling them to digest lactose in milk. This genetic mutation may have evolved thousands of years ago, providing an evolutionary advantage to Europeans who could drink milk.