For example a forest, if there is a small lake and many animals live there then the resourcewill be lower and the food source (animals eating each other) will be higher but if they eat plant the plants will be lower since many are competing for the same food source
Carbon dioxide is a greenhouse gas and traps heat in the atmosphere. Without it and other greenhouse gases, Earth would be a frozen world. But humans have burned so much fuel that there is about 30% more carbon dioxide in the air today than there was about 150 years ago, and Earth is becoming a warmer place.