Which of the following statements best describes 21st-century migration flows to the united states?

The 21st century marked the greatest wave of immigration in the history of the US. Immigration was great in number but in terms of its relative impact to the society it is just minimal. This type of immigration is the biggest compared to the past 100 years. It is marked by the series of influx of different people coming from different parts of the world that are either just visiting or are staying for good in the country.

Air pollution: “combustion results in gases such as nitrogen oxides, nitrogen dioxide and particulates. the main causes of air pollution include transport, domestic combustion and industrial processes. pollutants from these sources can cause problems in the immediate vicinity and a distance away.”