Image 1. A Duterty's wings lifted during off. As the wings snap together in a wing clap, they will propel the butterfly forward. Photo Stephen Dalton Science Source Photo: Stephen Dalton Science Source
Butterflies flutter when they fly. This is thanks to their large wings. This fluttery flight helps them
get away quickly from predators. Now scientists at Lund University in Sweden know how they do
it.
They clap their wings above them when they take off. This creates jet propulsion. This is the act of
pushing an object in one direction by ejecting a liquid or gas, such as air, in the opposite
direction. Aircraft like planes use jet propulsion to get off the ground. And now, scientists know
that butterflies use this method, too. In January 2021, scientists published their findings.
Studying Butterflies
Christoffer Johansson and Per Henningsson led the new study. They are evolutionary ecologists.
They study how flight has developed in animals.

Which of the following is an example of the treatment technique for ocd called exposure and response prevention (erp)? a. callie has a hoarding compulsion. she becomes anxious whenever she has to throw something away; she even keeps stuff that she doesn't need and will never use. her therapist has arranged for callie's unnecessary belongings to be discarded of when she is away from home. b. carrie has an obsessive fear of contamination which has led to compulsive hand washing. her therapist is treating her by making her touch dirty laundry but not allowing her to wash her hands following for increasingly longer periods of time. c. kelly has religious obsessions. she feels that if she doesn't read biblical passages every hour of the day, she will do something evil. her therapist is treating her by having her attend religious services more frequently so that good thoughts will replace the bad ones. d. kerry has an obsessive fear of contamination which has led to compulsive hand washing rituals. her therapist is treating her by forcing her to wash her hands repeatedly, even when she doesn't feel anxious.