A HUGE asteroid is thought to have hit Earth near Mexico 65 million years ago which sent up so much dust that it actually blocked the Sun for many years. Because of this, plants were not able to undergo:

Agroup of engineering students from purdue university reported that its licking machine, modeled after a human tongue, took an average of 364 licks to get to the center of a tootsie pop. twenty of the group's volunteers assumed the licking challenge-unassisted by machinery-and averaged 252 licks each to the center.

That’s easy the answer is 42