What is true about natural gas?

Natural gas is primarily composed of methane, which is a colorless and odorless gas in its natural state. To ensure safety and detection, a mercaptan odorant is typically added to natural gas, imparting a distinct smell that helps in identifying leaks. This characteristic is vital for safety reasons, as the absence of scent would make it difficult for individuals to notice a gas leak, which can pose significant dangers.

The statement that natural gas is not toxic is also accurate; while it is a flammable gas, it does not pose direct toxicological effects when present in typical residential concentrations. However, it is important to note that in very high concentrations, it can displace oxygen and potentially lead to asphyxiation, but this is different from being classified as toxic in the same manner as other hazardous substances.

Therefore, the correct answer encapsulates both the lack of color and odor in its natural form and the fact that it is not inherently toxic, aligning with proper safety and scientific understanding of natural gas properties.