Why use absorption spectra not emission to identify gas?

It may seem remarkable that we can learn about the composition of distant stars by studying the light they emit. In fact, we can learn a great deal, not only about the chemical elements present, but also about physical conditions. The key is to spread the light out by color, producing a spectrum like the one shown in Fig. 1. This lab explores some of the basic ideas used to analyze spectra.

answer: any goods being imported from another country may be subject to issued by the federal government are tariffs

explanation:  

tariffs are a tax on anything that are imported from abroad. government use them to protect and boost their local industries and the thought is that they encourage consumers to buy local instead of importing and they will hope will protect jobs and economy in the country that implements them