Lydia Denworth wants you to make more time for your friends.

We don't fully appreciate our friendships, says the science writer and author of the new book Friendship: The Evolution, Biology, and Extraordinary Power of Life's Fundamental Bond. If we did, we'd take cultivating those intimate bonds as seriously as working out or eating well. Because, she writes, a new field of science is revealing that social connections play a vital role in our health.

Michael Tafolla says the books he read in prison helped him understand how he had landed there in the first place. He remembers one especially eye-opening title: Illegal: Reflections of an Undocumented Immigrant.

"The main topic of this book is how a human being is reduced to an action that's perceived by others to be wrong," Tafolla says. "And therefore he is not a human being, but he is a walking, talking, breathing crime act."

It's caucus day in Nevada!

Today's election will feature the most diverse electorate yet in this Democratic presidential nominating contest. And it presents a challenge for each of the candidates in the race. Vermont Sen. Bernie Sanders, who finished second in Nevada in 2016, is the favorite in yet another race, as the more moderate candidates continue to duke it out.

Here are six things to watch:

Where there was a white ice cap, there are now brown blotches of land; melted snow and ice have created ponds of water. Those are the effects of the recent record high temperatures in Antarctica, according to NASA, which on Friday released stunning before-and-after satellite images of the northern Antarctic Peninsula.

Updated at 6:38 p.m. ET

Former New York City Mayor Michael Bloomberg said Friday that he will permit his company to release three women from nondisclosure agreements with his company, a reversal after resisting to do so under pressure from his rivals at a Democratic presidential debate earlier this week.

In a statement released Friday afternoon, Bloomberg said that Bloomberg LP had identified three nondisclosure agreements made with women "to address complaints about comments they said I had made."

Wells Fargo has agreed to pay $3 billion to settle charges that the bank engaged in fraudulent sales practices for more than a decade.

The company acknowledged collecting millions of dollars in fees for bank accounts, debit cards and other products that customers neither asked for nor needed. The illegal practices were carried out by thousands of Wells Fargo employees in order to meet unrealistic sales targets.

The Horn of Africa, one of the world's most impoverished regions, is being ransacked by billions of tiny invaders.

Farmers look on in horror as desert locusts moving in vast cloud-like swarms darken the sky. The insects blast through fields of crops at an astonishing pace, decimating livelihoods in the process.