Answer:
The circulatory system has evolved over time from simple diffusion through cells, in the early evolution of animals, to a complex network of blood vessels that reach all parts of the human body. Made of specialized and unique cardiac muscle, it pumps blood throughout the body and to the heart itself.
Claps shut at birth. Evolutionary changes in the vertebrate heart are tied to change from single to double-circuit heart, with increased separation of oxygenated and deoxygenated blood, allowing more efficient respiration and circulation to fuel high activity and increased oxygen demands associated with endothermy.
 
        
             
        
        
        
If my letter guessing is right i would go with A or the first one
        
                    
             
        
        
        
Deletion because it worse then a substitution since your deleting something
        
             
        
        
        
Answer:
mitochondria and chloroplast 
Explanation:
Mitochondria : generates energy
Chloroplast : converts energy from solar energy to chemical energy in form of ATP
 
        
                    
             
        
        
        
The correct answer is option B, that is, the release of large amounts of greenhouse gases can change Earth's climate.
Fossil fuels refer to hydrocarbons, mainly fuel oil, coal, or natural gas, produced from the leftovers of dead animals and plants. The use of fossil fuels has allowed large-scale industrial development and hugely supplanted water-driven mills, as well as the combustion of peat or wood for heat.  
The burning of fossil fuels by humans is the biggest source of emissions of carbon dioxide that is, one of the greenhouse gases, which permits radioactive forcing and donates to global warming. One of the dreadful effects of global warming is the change in the climatic condition of Earth.