Answer : 4. "All the above"
Explanation :

Answer: D) All the above Explanation: Global warming is the increase in the earth’s average temperature due to release of several greenhouse gases to the atmosphere by humans. Global warming is affecting many parts of the world.   Natural Causes include : 1. Solar Activity 2. Melting Permafrost 3. Forest Fires    Human made causes include : 1. Deforestation 2. Overpopulation 3. Landfills 4. Mining 5. Fertilizer Use