Option 1: Ozone does contribute to the greenhouse effect, but it is not the major contributor. Ozone is a gas that is found in the Earth`s stratosphere and plays a vital role in absorbing harmful ultraviolet (UV) radiation from the sun. While ozone can absorb some infrared radiation, which is associated with the greenhouse effect, its overall contribution to the greenhouse effect is relatively small compared to other greenhouse gases such as carbon dioxide.

Option 2: Carbon dioxide is indeed a major contributor to the greenhouse effect. It is a greenhouse gas that is released into the atmosphere primarily through the burning of fossil fuels such as coal, oil, and natural gas. Carbon dioxide traps heat in the Earth`s atmosphere, which contributes to global warming and climate change.

Option 3: Carbon monoxide is not a significant contributor to the greenhouse effect. It is a colorless and odorless gas that is produced from the incomplete burning of fossil fuels. While carbon monoxide can have harmful effects on human health and the environment, it does not have a significant impact on the greenhouse effect.

Option 4: Water vapor is the correct answer. It is the most abundant greenhouse gas in the Earth`s atmosphere and plays a crucial role in the greenhouse effect. Water vapor is naturally present in