The reading passage presents three strategies to reduce the heat in cities, but the professor in the lecture points out several problems with each approach. First, the reading suggests planting vegetation on rooftops, known as green roofs, to cool buildings. However, the professor explains that only a few plant species can survive the harsh conditions on roofs, such as strong winds and thin soil. The species that do survive do not provide the cooling effect that is expected from plants in parks. As a result, green roofs are unlikely to be effective. Second, the reading recommends using water-absorbing pavements to cool cities through evaporation. While this could work in areas with regular rainfall, the professor notes that in dry climates with little rain, these pavements would actually retain more heat. The porous structure of the pavements increases their surface area, causing them to absorb more heat from the sun, which exacerbates the heat problem. Finally, the reading suggests that designing denser urban areas could reduce car usage and lower temperatures. Although this approach might reduce heat from motor vehicles, the professor argues that it would increase human body heat. In dense cities, the heat produced by people becomes concentrated, resulting in similar temperature levels to those in spread-out cities where car usage is more common. In conclusion, while the strategies proposed in the reading may seem effective at first, the professor reveals significant drawbacks that limit their ability to reduce heat in cities.