A U.S.-South Korean agreement on strengthening deterrence against North Korea will discourage Seoul from seeking nuclear weapons, but also shows the inability to remove the threat of Kim Jong-Un's arsenal. The long-running danger has led many in South Korea to call for building its own nuclear arms. Seeking to head off such a move, the U.S. has agreed to more cooperation with Seoul on nuclear issues and the regular deployment of strategic assets to the Korean Peninsula.

HOW A US NUCLEAR SUB SENT A MESSAGE TO NORTH KOREA

The U.S. will step up deportations while also expanding legal pathways for would-be migrants as it braces for a possible spike in illegal border crossings when COVID-19 restrictions are set to end in May. The U.S. will double or triple the number of deportation flights and aim to process migrants crossing the border illegally "in a matter of days." The U.S. also will expand legal options for migrants, encouraging them to apply for entry at two new processing centers in Guatemala and Colombia.

WILL PROCESSING CENTERS CURTAIL ILLEGAL IMMIGRATION?

Scientists on Thursday unveiled the results of a project comparing the genomes of 240 mammal species - from aardvarks to zebras, as well as people - to trace evolutionary changes spanning 100 million years, pinpointing genetic traits widely shared and those more uniquely human. The findings in the ambitious Zoonomia Project could inform human therapeutics, critical care and long-distance space flight.

SEE THE TRAITS THAT MAKE HUMANS UNIQUE FROM ANIMALS

According to the Human Genome Project, how much common DNA is shared between modern human beings and chimpanzees?

Thursday's answer: Charles Tiffany co-founded Tiffany & Co in 1837. The company introduced America's first mail-order catalog in 1845.