Read this passage from a brochure about climate change and how it may affect our health in the future. Diseases and Allergies
Diseases such as cholera and salmonella, which are transmitted through contaminated food or water, could become more widespread with climate change because of increased flooding.

Changes in temperature and rainfall in some areas are likely to increase the range and the length of activity for ticks and mosquitoes, which can spread diseases such as Lyme disease, malaria, and West Nile virus. In fact, the large transmissions of West Nile virus during the summers of 2002 through 2004 in the United States have been linked to the above average temperatures seen in these years. These impacts may be more prevalent in developing countries, however, since many climate-sensitive diseases such as malaria have been virtually eliminated in the United States due in part to public health measures.

Climate change could also cause more severe allergy symptoms because a warmer climate is expected to promote the growth of the molds, weeds, grasses, and trees that cause allergic reactions in some people. Climate change has already caused the spring pollen season to begin earlier in North America. Ragweed has been observed to grow faster and flower earlier in urban areas where effects of climate change are enhanced compared with rural areas.

What sentence best describes how this section is organized?

lists questions about health effects followed by answers
gives a step-by-step description of how climate change leads to illness
explains how climate change will affect three different categories of disease
explains a concept, then provides several examples of the concept