Answer: The innocent-until-proven-guilty principle is based on the presumption that an individual accused of a crime is considered innocent until proven guilty in a court of law. This principle is a fundamental part of the American legal system and is enshrined in the Fifth and Fourteenth Amendments to the United States Constitution.
Therefore, option i, "not used as a guiding principle in the United States," is incorrect.
Options ii and iii, on the other hand, are related to the precautionary principle, which is a separate concept related to environmental and public health policy. The precautionary principle is based on the idea that in situations where there is scientific uncertainty about the potential harm of a particular chemical or substance, it is better to err on the side of caution and take action to prevent harm before it occurs.
Option ii, "based on the idea that scientific research must demonstrate harm before a chemical can be outlawed," is an incorrect description of the precautionary principle. The precautionary principle suggests that in cases of scientific uncertainty, it is better to take action to prevent harm even in the absence of conclusive evidence of harm.
Option iii, "precautionary since it can prevent risk before proving a chemical is hazardous," is a correct description of the precautionary principle.