What gas is primarily responsible for providing color to plants?

The correct answer is nitrogen. In plants, nitrogen is a vital nutrient that is an essential component of chlorophyll, the green pigment responsible for photosynthesis. This pigment allows plants to absorb light, primarily sunlight, which drives the process of converting sunlight into energy. While plants produce a variety of colors through different pigments, the green color often associated with vegetation is primarily due to chlorophyll.

While carbon dioxide is crucial for photosynthesis, it does not provide color to plants. Instead, it is a raw material used in the photosynthetic process. Oxygen is a byproduct of photosynthesis and also does not contribute to the coloration of plants, as it is a colorless gas. Helium is not involved in plant processes and does not play any role in the coloration of plants. Thus, nitrogen's role in the formation of chlorophyll distinctly positions it as the gas that influences color in plants.