It stopped in 11,700 years ago
Environmental scientists are using GPS ( It is effective but expensive) aerial monitoring (Quick but not the easiest), RFID tags, (mostly for long-term monitoring) and hidden cameras are used to study polar bear behavior without interruption to their environment.
DNA sequencing technique runs through database so it can compares all the sequenced information and finds similarities.
The gasoline engine where the air and fuel mixture is burned is called the combustion chamber. A piston is used to increase and decrease the volume which prepares the fuel to be mixed with air. A spark plug is ignited then to create the combustion thereafter.