The following sentences contain blanks. Use the drop-down menus to complete each blank correctly. The building of both Washington, DC, and Manaus, Brazil, required deforestation, or the process of [Dropdown 1] to clear the land. To build the city of St. Petersburg, Russia, workers had to drain swamps and dig [Dropdown 2] to allow water to flow through the city. Construction in present-day Tokyo, Japan, requires the use of technology that allows tall skyscrapers to absorb seismic energy created by [Dropdown 3] .