Greenhouse gases are the cause of Greenhouse effect.The greenhouse gases which include CO2, Methane etc. trap the heat in the Earth's atmosphere and don't allow it to escape.
The weapon is fitted with a Leupold Mark 4. The rifle is also similar in appearance to the TAC-338 rifle that Kyle used in real life. McMillan TAC-338A sniper rifle with Harris bipod, Leupold Mark 4 scope, and AN/PVS-22 Universal Night Sight - .338 Lapua Magnum. Kyle taking aim with the rifle. Right side of the rifle.
Kyle was shot five times and Littlefield was shot four times. Most of the gunshots were in their backs. Both men were carrying handguns, but they were found still holstered in their waistbands with the safety on, according to witness testimony.