The organ is the LUNGS.
The lungs excrete carbon dioxide and water vapour through metabolism. 
The lungs are used for breathing in humans, through the lungs we take in oxygen which is carried by the blood to all the part of the body and we exhale carbon dioxide which is a waste product generated as a result of the reactions that occur in the body. 
        
             
        
        
        
The answer to this question is:
A. Haploid
        
                    
             
        
        
        
Answer:
3.  Endotherms spend more energy on internal temperature regulation compared to ectotherms.
Explanation:
Ectotherms, are considered  as cold-blooded animals (reptiles and amphibians),  and are organisms that don't have the ability to generate enough heat to keep themselves warm. Endotherms, in contrast, do possess the ability to generate their own body heat.
Endotherms also called warm blooded animals  (mammals) have the ability to regulate their body temperature by themselves. If the endotherms are in a cold place their body increases the metabolism and generates more heat. This will compensate for the cold outside.
 
        
             
        
        
        
Answer:
The correct answer is C) There is a larger variety of MHC proteins that can be expressed on the cell surfaces of their immune cells, providing a wider opportunity to recognize and attack pathogens.
Explanation: