In the late 1800s, long-distance communication was difficult. Though there was a postal service, it was slow and unreliable. Letters could take many weeks or even months to travel cross country. Quickly reaching a faraway loved one in an emergency was only possible via the electric telegraph, which was not available to everyone. In contrast, today Americans communicate freely, inexpensively, and frequently over all distances with cell phones and computers. Friends and family, no matter how distant, are only a push of a button away. Which word or phrase makes the transition to a different idea

The word or phrase that makes the transition to a different idea in this excerpt is "in contrast."

Explanation:

In English language, there are certain words or phrases that are used to connect ideas, sentences or paragraphs. These words or phrases are called linking words. There are many types of linking words classified according to their function, for example:

In this excerpt, the phrase in contrast is used as a linking word to show a transition to an opposite idea within the same paragraph and compare communication in two different time periods.

i just did something on this guy a few days a go give me two minutes to find it in my notes.