The sentence that best expresses a sense of urgency in a claim is In his doctoral thesis, A Bright Tomorrow?, Dr. Smith insisted that if we do not lower carbon emissions, the earth may be inhabitable by the year 2050.
This refers to the statement or assertion that is used to talk about a thing that may be true or false.
Hence, we can see that The sentence that best expresses a sense of urgency in a claim is In his doctoral thesis, A Bright Tomorrow?, Dr. Smith insisted that if we do not lower carbon emissions, the earth may be inhabitable by the year 2050.
Read more about claims here:
https://brainly.com/question/2748145
#SPJ1