What are greenhouse gases? What are the sources of these greenhouse gases?

Greenhouse gases are gases that trap heat in the Earth’s atmosphere. Examples of greenhouse gases are carbon dioxide and methane. Too much of these greenhouse gases can result in global warming.
The sources of these gases:
1. Carbon dioxide
Carbon dioxide is released to the atmosphere mainly through the combustion of carbon-containing fuels, and the respiration of living organisms.
2. Methane
Methane is released to the atmosphere mainly through the decomposition of organic matter and from flatulence from livestock like cows, goats.