They all contain at least one cell, and they need need food, water, energy, and living space to survive. They are both considered living organisms as well. They depend on abiotic and biotic factors in an ecosystem to survive.
        
             
        
        
        
The correct answer is:
D
.Villi in the small intestine have thin-walled capillaries to make the absorption of nutrients more efficient.
Explanation:
The small intestines are well adjusted for absorbing nutrients during digestion by being very long, having villi and microvilli that enlarge surface area, using muscular contractions to move and mix food, and raising and housing digestive enzymes and bile that aid the breakdown of food. The inner surface of the small intestine is not flat but thrown into circular folds, which not only enhance surface area but aid in preparing the ingesta by acting as baffles. Villi: the mucosa makes multitudes of ridges which project into the lumen and are satisfied with epithelial cells.
 
        
                    
             
        
        
        
1. GLYCOLYSIS
2. KREBS CYCLE
3. ELECTRON TRANSPORT CHAIN 
 
        
                    
             
        
        
        
Your blood vessels dilate which is called vasodilation, this allows your blood to carry out the excess heat from inside your body to the outside.
        
             
        
        
        
Answer:
I wasn't quite sure what virus you were referring to in your question, but here's a general answer: Viruses use their host cells' machinery to replicate themselves. 
If they are a specific type of virus known as a retrovirus, they have the ability to use the host cells' enzymes to change the RNA contained within the virus into DNA (via some type of replication I suppose). 
In other cases, if they contain DNA instead of RNA (that is, the virus), they can use the host cell's machinery to create RNA via enzymes involved in transcription and/or they can incorporate that DNA into the host cell's DNA. This is part of a type of viral replication cycle known as the lysogenic cycle. 
In another type of viral replication cycle known as the lytic cycle, the virus simply has itself and its genome duplicated until the host cell bursts, releasing the viral material. Here, again, the virus uses the host cell's machinery to replicate itself.