segments

The mutations, known as copy number alterations, involve the duplication or loss of large segments of DNA.

Unlike today’s earthworms, these 1-centimeter fossils, called Uncus dzaugisi, lack any segments and had an outer coat stiff enough to keep them from being completely flattened as sediments accumulated on top of them.

New segments then emerge by the division of these cells.

So do comedians like Jimmy Kimmel, whose roving segments regularly entertain the audience with gleeful reminders of how little the public knows about . . . everything.

Weekend walks range from eight to 15 miles, “loop” segments are typically 20 miles in a day.