President Joe Biden delivered a budget proposal that amounts to his expected 2024 reelection pitch on Thursday with the unveiling of a proposed budget protecting free health care for the elderly, while taxing wealthy Americans to help slash the national deficit. Biden threw down the gauntlet to Republicans, who insist the priority is cutting the deficit without tax raises, but have yet to say what expenses they'd reduce. That standoff comes amid a potential crisis over the national debt.

SEE THE REACTION TO BIDEN'S PROPOSAL FOR 2024 BUDGET 

The head of U.S. rail operator Norfolk Southern pledged Thursday to improve safety practices and quickly address clean-up needs after its train derailed and spilled toxic chemicals in an Ohio town last month. But even as CEO Alan Shaw apologized before Congress for the Feb. 3 disaster in East Palestine, Ohio, and a second one in Ohio last week, as one of the company's trains came off the rails Thursday in Alabama.

HOW NORFOLK SOUTHERN EXPLAINED SERIES OF CRASHES

A dwarf elephant the size of a Shetland pony once roamed Cyprus. In the West Indies, a 400-pound rodent once ruled. They were examples of the "island effect," a rule in evolutionary biology describing how large-bodied species tend to downsize on islands while small-bodied species upsize. Such island dwarfs and giants are at the heart of a new study that shows some of Earth's most unique creatures are in peril.

SEE WHAT THE STUDY SAYS ABOUT TODAY'S 'ISLAND EFFECT'

What is the largest animal ever known to exist on the planet Earth?

Thursday's answer: Thin Mints are by far the top-selling Girl Scout cookie, accounting for 25% (about 50 million boxes) of its annual sales.