1. We know the earth is getting warmer because temperatures have risen all around the globe. Also, the Arctic is melting. 2. The Earth temperature changes because of green house gases and harmful gases being sent into the atmosphere. 3. The greenhouse effect is a process that occurs when gases in Earth’s atmosphere trap the Sun’s heat. 4. Factories. 5. It could cause more flooding and a rise of warmer temperatures. 6. Permafrost is ground that continuously below 0 degrees Celsius for two or more years.
Although more complex animals like invertebrates and multi-celled organisms began to appear, it was very late compared to the original, simpler organisms for which the Precambrian time is characterized by.
