Election supervisors are reminding Floridians: Signatures change over time.

A House education panel on Thursday began delving into the issue of raising teacher pay, with a key lawmaker saying that while "everything is on the table," the panel still needs to figure out where the money would come from.

Scientists have discovered a mash-up of two feared disasters — hurricanes and earthquakes — and they're calling them "stormquakes."

Updated at 10 a.m. ET

Heavily armed gunmen went on a shooting rampage through the city of Culiacán, the capital of Sinaloa state on Mexico's Pacific coast, battling security forces after authorities attempted to arrest a son of imprisoned drug lord Joaquín "El Chapo" Guzmán.

The gunfire from what appeared to be sniper rifles and truck-mounted machine guns sent residents of the western city scrambling for cover. Burning vehicles littered the streets as the gunmen faced off against the National Guard, army and police.

Sounding like a huge swarm of angry bees or maybe a hedge trimmer on steroids, a small quadcopter lifts up off of a landing pad in front of the main hospital building on the WakeMed campus in Raleigh, N.C. Underneath it is a metal box — smaller than a shoebox — with vials of blood samples inside of it that are now heading across the campus to the lab for analysis, guided by a drone operator on the ground.

It's not a long trip.

Each week — and some days, it seems, each hour — brings more clarity to the picture of the Ukraine affair and the political crisis it sparked in Washington over impeachment.

But some of the biggest questions still don't have answers.

Here's a look at where the saga stands, what investigators want to learn and what major decisions still must be reached before the fever breaks.

The Ukraine affair

No one disputes the basic outlines of the Ukraine affair, including President Trump:

Updated at 6:30 p.m. ET

Secretary of Energy Rick Perry plans to leave his position at the end of the year, President Trump confirmed to reporters Thursday in Fort Worth, Texas. Trump praised Perry and said he already has a replacement in mind.

"Rick has done a fantastic job," Trump said. "But it was time."

Trump said that Perry's resignation didn't come as a surprise and that he has considered leaving for six months because "he's got some very big plans."