The answer is vehicle fuel
The esophagus has a simple but significant functions to animals who has it. These functions can be a) to swallow food and serve as a passageway to the stomach and b) may serve to release the eaten food that might have some harmful compositions or chemicals -the vomit response.
I believe the biosphere is fragile, because over time all of the pollution us humans have made; If its from air pulloution, acid rain or even water pollution. the toxic acids over time have made the biosphere and the ozon layer weaker and more thin. which causes the biosphere to become weaker.
Publication in journals
you see that a lot today
<u>Hugs ~L</u>