8 p.m. on 2, 9, ‘‘Extreme Weight Loss’’ — The hit series — formerly known as ‘‘Extreme Makeover: Weight Loss Edition’’ — returns for a third season as transformational specialist Chris Powell sets out to change the lives of twins who work together to shed weight, a married couple with the same goal and an amputee who wants to shed the pounds he gained after losing his limb.

8 p.m. on 7, ‘‘In Performance at the White House’’ — In the new episode ‘‘Carole King: The Library of Congress Gershwin Prize for Popular Song,’’ the prolific singer-songwriter becomes the first woman to receive this prestigious award. Among those helping honor her are James Taylor, Gloria Estefan, Trisha Yearwood and Emeli Sande.

9 p.m. on 5, 8, ‘‘The Voice’’ — And then there were six. After a recap of Monday’s performances by the eight remaining finalists, the votes of viewers at home determine which two artists — one from each team — go home, sending the remaining six to the next phase of competition in the new episode ‘‘Live Eliminations.’’ Carson Daly hosts.

9 p.m. on 7, ‘‘CONSTITUTION USA With Peter Sagal’’ — In the final episode Peter Sagal travels to Iceland, where after the country’s economic collapse, leaders decided to create a new constitution, looking to the U.S. Constitution for inspiration. This prompts Sagal to consider why our own founding document has lasted more than 225 years. He looks at the systems that have kept the Constitution healthy and the political forces that threaten to undermine the framers’ vision in ‘‘Built to Last?’’

10 p.m. on 2, 9, ‘‘Body of Proof’’ — Accompanied by Tommy (Mark Valley), Megan (Dana Delany) attends the exhumation of her father’s body, which raises more questions about his death than it answers. Joan (Joanna Cassidy) suggests Megan look into his patient files, where she also might find a clue about another death, in the season finale, ‘‘Daddy Issues.’’ Jeri Ryan and Geoffrey Arend also star.

10 p.m. on 6, ‘‘Brooklyn DA’’ — From the team behind ‘‘48 Hours’’ comes this new six-part series that looks at the larger-than-life personalities who make up the Kings County District Attorney’s Office in New York, one of the largest in the country, where the staff juggles more than 1,000 cases per week.