Answer:
c
Explanation:
A habitat defines the interaction of organisms with the other factors, which can be living or non-living, while niche describes how that specific organism is linked with its physical and biological environment. Habitat is the part of the ecosystem, while niche plays an important role in the formation of an ecosystem.
 
        
                    
             
        
        
        
By the term "condensed", this refers to the density of a state of matter. As a rule of thumb, solids are the most dense because their molecules are very close together. Next is liquids because they flow compared to solids. The least dense are gases. Therefore, a change from a more condensed state to a less condensed state is boiling (liquid to gas).
        
             
        
        
        
Answer: A.
Explanation:
Proteins are the things that determine what functions will play out. They are the reason we are able to digest foods, transfer oxygen throughout the body. Proteins MAKE these functions happen. Without proteins, we wouldn't be able to do anything
 
        
             
        
        
        
I believe the answer to this question is a food web.
Food Web definition: "<span>a series of organisms related by predator-prey and consumer-resource interactions; the entirety of interrelated food chains in an ecological community." 
Source: </span>http://www.dictionary.com/browse/food-web
        
                    
             
        
        
        
Answer:
decreases amount of energy necessary for reaction to proceed
Explanation:
they lower activation energies of the reactions they catalyse