I need help with this global warming question

Tropospheric ozone is a major component of smog, which can worsen bronchitis and emphysema, trigger asthma, and permanently damage lung tissue. Tropospheric ozone exposure is responsible for an estimated one million premature deaths each year. Children, the elderly, and people with lung or cardiovascular diseases are particularly at risk of the adverse health impacts of ozone.Tropospheric ozone is a highly reactive oxidant that significantly reduces crop productivity as well as the uptake of atmospheric carbon by vegetation. Its effects on plants include impeded growth and seed production, reduced functional leaf area and accelerated ageing.

Studies have shown that many species of plants are sensitive to ozone, including agricultural crops, grassland species and tree species. These effects impact on the important ecosystem services provided by plants, including food security, carbon sequestration, timber production, and protection against soil erosion, avalanches and flooding.

well, i believe that the answer is 2. : 3