All humans digest mother’s milk as infants, but until cattle began being domesticated 10,000 years ago, children once weaned no longer needed to digest milk. As a result, they stopped making the enzyme lactase, which breaks down the sugar lactose into simple sugars.

After humans began herding cattle, it became tremendously advantageous to digest milk, and lactose tolerance evolved independently among cattle herders in Europe, the Middle East and Africa. Groups not dependent on cattle, such as the Chinese and Thai, remain lactose intolerant.

Which among the following is the most logical assumption that can be made from the above passage ?

The correct option is: A permanent change in the food habits of a community can bring about a genetic change in its members.

Step-by-step Explanation:

1. Analyze the Premise: The passage describes a historical shift in human diet. Initially, humans stopped producing the enzyme lactase after weaning because milk was no longer part of their diet. However, around 10,000 years ago, certain human populations domesticated cattle and began consuming milk regularly (a permanent change in food habits).

2. Identify the Consequence: Because of this dietary shift, being able to digest milk (lactose tolerance) became a massive evolutionary advantage. Consequently, lactose tolerance evolved independently in these cattle-herding populations (a genetic change allowing the persistence of lactase production into adulthood).

3. Observe the Control Group: The passage also notes that communities that did not domesticate cattle or rely on milk (such as the Chinese and Thai populations) did not undergo this evolutionary adaptation and remain lactose intolerant. This confirms that the genetic change (lactose tolerance) was directly linked to the permanent dietary change (milk consumption via herding).

4. Draw the Logical Assumption: Combining these observations, we can logically assume that a long-term, permanent shift in a community's diet (such as domesticating cattle and drinking milk) acts as a selective pressure that can eventually lead to genetic adaptations (such as retaining the ability to digest lactose) in its members. This directly aligns with the correct option.