Which gas is characterized by being colorless, tasteless, and odorless while not supporting life?

Helium is indeed characterized as being colorless, tasteless, and odorless, making it a unique inert gas. Unlike many other gases, helium does not support combustion or life, which is a critical aspect to note when studying gases. Its lack of reactivity means that it does not engage in chemical reactions with other substances under standard conditions, which is why it is often used in applications where non-reactive gas is needed, such as in balloons or as a cooling medium in certain technologies.

In contrast, carbon dioxide is a colorless gas but has a slightly sharp odor and is critical for life as it is a byproduct of respiration and is utilized in photosynthesis. Oxygen is essential for the respiration of most living organisms and is also a colorless gas, while nitrous oxide, although colorless and having a slightly sweet odor, is known for its use as an anesthetic and has important biological functions in the human body. Therefore, the characteristics of helium make it the correct choice as it fits the description of a non-supporting life gas that is also colorless, tasteless, and odorless.