Answer: B
Counting the number of touches
Credible · University of Würzburg
You might think they snap shut at the slightest touch, but Venus flytraps are smarter. Research shows they can count to five: the 1st touch primes the trap, the 2nd (within 30 seconds) snaps it shut to avoid false alarms like raindrops, and by the 5th touch, the plant is sure it has a meal and starts producing digestive enzymes. This calcium-based 'counter' prevents wasting energy on false alarms.
Search 'Venus flytrap counting' on YouTube to see this biological calculator in action. Quiz that friend who claims they 'hate math'—they probably never realized even a plant has to count to survive.
