Diagnoses for several cancers before age 50 have been increasing rapidly since the 1990s. Scientists don’t know why, but they have a few suspects.

Demonstrated in rabbits, the 3-D printer might someday print bone grafts directly onto fractures, complete with antibiotics to ease healing.

Dogs that easily learn the names of toys might also mentally sort them by function, a new example of complex cognitive activity in the canine brain.