Answer: ecosystem
An ecosystem is a community of living and non-living components. A coral reef is an aquatic ecosystem which is formed by a continuous walls of calcium carbonates released by living animals they get combine to form rocks. These rocks and walls are collectively called as hard stony corals. These hard stony corals provide shelter to many aquatic animals like fishes. As the water is the chief abiotic factor along with coral walls and rocks which help in the survival of living organisms therefore, ecosystem is the largest organizational level found in one coral reef. 
 
        
                    
             
        
        
        
I think that it would be classified in the prokaryotic domain.
        
             
        
        
        
Answer:
a) Because when we exercise, we hydrolyze more ATP to ADP and Pi, and O2 is necessary for the hydrolysis, so we increase our intake of oxygen.
c) Because when we exercise, we produce more CO2 and increased ventilation is necessary to rid ourselves of CO2.
d) Because when we exercise, we use more ATP, and additional O2 is necessary to generate sufficient ATP.
Explanation:
During exercise , our body needs more energy in the form of ATP. This ATP comes from break down of food materials in the mitochondria of the cell during cellular respiration. With the addition of oxygen, more ATP is produced during respiration and this ATP is used by the body. With ATP, carbon dioxide is produced as a waste material which can be removed by exhaled out during breathing.
 
        
             
        
        
        
1. Make a goal for yourself. When you finish your fitness program(achieve your goal) you can reward yourself with like icecream or a small treat.
2. Make working out fun so that you will keep wanting to do it. For example, work-out or go to the fitness program with a friend, listen to music while doing it, etc.
3. You can make yourself motivated by watching fitness videos and basically watching things to get inspiration(trust me this works).After you watch the vids, your gonna want to keep going to the fitness program cause of all the benefits and things like that. 
4. Ask a friend or someone to push you to keep going(if all else fails and you wanna quit) They will annoy you so much that it would just be better to go to the fitness program than hear them annoy you.
5. Think why your going to regret not going. This is gonna make you want to go to the fitness program.
6. Honestly if the others don't work, do it for the pictures and so that you can brag to people that you work out and stuff. 
That's all I got for now. Hope it helped motivate you to keep going to that fitness program <span />