Which inference can be reasonably drawn from Passage 1?

The inference that a large percentage of the human population suffers from illnesses caused by toxic chemicals in the environment can be reasonably drawn from Passage 1, especially if the passage discusses the detrimental effects of environmental toxins on human health. This statement suggests a direct relationship between exposure to harmful substances in the environment and health problems, which aligns with commonly accepted views in public health and environmental science.

The emphasis on the impact of toxic chemicals implies that these substances are significant contributors to health issues faced by individuals, supporting the idea that many people are affected by such environmental factors. The phrasing "large percentage" indicates that this is not an isolated issue but rather a widespread concern, drawing attention to the severity of the problem.

In contrast, the other options present claims that do not align with the likely assertions made in the passage. For instance, stating that most of the human population enjoys perfect health is overly optimistic and does not take into account the numerous health challenges faced globally. Similarly, asserting that environmental toxins are harmless contradicts the likely context of the passage, which presumably highlights the dangers posed by such substances. Finally, the claim that the environment has no impact on health ignores the established evidence of how environmental factors can influence general health outcomes.