Dutch elm disease spread more rapidly in the United States than in Europe because of the 1. practice of planting elms in monoculture 2. plentiful breeding sites for beetle vectors due to elm phloem necrosis 3. narrow genetic base of susceptible American elm trees 4. none of the others 5. all of the others

The table presents the average day and night temperatures in five cities. it also reveals whether a city receives substantial rainfall (wet climate) or little rainfall (dry climate). which city’s rocks are likeliest to experience frost wedging, and why? a) city a because the consistently subzero temperature would prevent water from melting b) city b because it is a wet region and the temperature fluctuates around the freezing point c) city c because it receives plenty of rain fall and the weather is moderately cool d) city d because the hot and dry weather would cause rocks to absorb water