Correct Option (B)
Assumptions 2 and 4 are valid based on the provided passage.
- The passage indicates that farmers in the past "painstakingly bred and developed crops well suited to the peculiarities of their local climate and environment," which implies that the consumption of food mainly from locally cultivated crops contributed to crop diversity. The subsequent decline in diversity is linked to a departure from this practice.
- The passage explicitly states, "If some mutating crop disease or future climate change decimates the few crop plants we have come to depend onto feed our growing population, we might desperately need some of those varieties we have let go extinct." This directly supports the assumption that food security depends on the ability to preserve locally cultivated varieties of crops, as these represent a genetic resource against future threats.
Incorrect Options:
- Assumption 1 is not directly supported by the passage. While the passage attributes the dwindling of diversity in food crops to human practices (heavy dependence on a few high-yielding varieties), it does not make a generalized claim that humans are the main reason for the large-scale extinction of all plant species. The scope of the passage is specific to food crop varieties.
- Assumption 3 is an overstatement. The passage warns that the current style of production and distribution could lead to problems if diversity is lost ("we might desperately need some of those varieties"), implying a potential risk rather than a definitive outcome of food scarcity in the near future. It highlights a vulnerability, not an inevitability.