The main source of carbon dioxide in an ecosystem is the carbon dioxide gas present in the atmosphere. This carbon dioxide is used by the  plants and animals in different ways.
The plants use this carbon dioxide to perform the process of photosynthesis.This is carried out by the help of green pigment called chlorophyll that absorbs light from the sun, water from soil and carbon dioxide from atmosphere.
The carbon in animals comes when they eat these plants.
 
        
             
        
        
        
1 = Blizzard 
2 = Tornado
3 = Thunderstorm
4 = Hurricane
5 = Hailstorm
        
             
        
        
        
The full form of ISP is, Internet service provider (ISP), company that provides Internet connections and services to individuals and organizations. ISPs are all connected to each other through network access points, public network facilities on the Internet backbone.