In this task, we ask you to rewrite a sentence in simple English without changing its general meaning. Essentially, you want to make the sentence easier to read by using simpler words, utilizing more straightforward sentence structures, and omitting non-essential information etc.

The Massachusetts Bay Transportation Authority ( abbreviated MBTA and known colloquially as " the T " ) is the public agency responsible for operating most public transportation services in Greater Boston , Massachusetts .
The Massachusetts Bay Transit Authority ( usually called the MBTA or " the T " ) is Massachusetts ' public transportation system .

Alternatively , the image may be projected onto a translucent " rear projection " screen , often used for continuous automatic display for close viewing .
The image may be projected onto a translucent " rear projection " screen .

Popular sovereignty is the principle that the authority of a state and its government are created and sustained by the consent of its people , through their elected representatives ( Rule by the People ) , who are the source of all political power .
They give their permission through their elected representatives ( Rule by the People ) , who is the source of all political power .