There are different trophic levels at each stage. Trophic levels determine the amount of energy at each stage of the food chain. For example, the energy is 100% at the producer (plant), so it's the 1st trophic level, and so on. Energy amounts decrease as you go up a food chain, and you rarely find more than 5 animals in one because there is not enough energy left for the 6th consumer
        
             
        
        
        
Reduce carbon dioxide emissions, pollution, and deforestation
reuse materials rather than throwing them away and needing to create more
recycle materials like metals, paper, and plastics
replace non-biodegradable materials with biodegradable
        
             
        
        
        
It is useful for an ecologist to identify the keystone species in an ecosystem because the keystone species is important to maintaining the stability of an ecosystem, and any changes in the keystone species population shows that there is changes in ecosystem health.
 
        
             
        
        
        
Answer:
Basically, the Atrioventricular valves are Mitral and Tricuspid valves located between the atrium and ventricles. Their main functions is to “prevent the backflow of blood from the ventricles into the atrium during the ventricular contraction (systole).
Explanation:
 
        
             
        
        
        
Answer:
It stores glucose that is taken from food so that respiration can happen later.