B. acidity...
hope this helps and HAGD!
The answer is B. Geology has shown a thin layer of iridium (a rare mineral on earth but found on asteroids and meteors) in the rock layers between the Cretaceous and Paleogene periods. Below this layer are numerous fossils of pterosaurs and dinosaurs, but above the layer are drastically few. The aftermath of asteroid impact is believed to have smothered most vegetation from earth which dinosaurs depended on as a source of food.
There may be a shortage of clean drinking water in the future
I believe the appropriate answer is a cooling-off period. The cooling off period us described as the state of returning to the offender's usual way of life between homicides. The key distinction between the serial killers and mass or spree killers is this emotional cooling off period in which the killer blends back into his/her normal life.