Answer:
Parasitic
Explanation:
The species that is described is a parasitic species. The reason why it will fall into this category is that its key feature is that it is entirely dependent on other organisms for its food. This type of species are not able to produce food for themselves, nor are able to get it from the environment, which is way they have evolved in a manner to use the other organisms. They find a host organisms, attach to it, and then they are extracting the nutrients out of that organism, thus classical parasitism. The extraction of the nutrients can be so severe that the parasitic species can actually kill systemically its host.
 
        
                    
             
        
        
        
Answer: Ecology!
I hope that this helps! :)
        
             
        
        
        
Answer:
Yes and no
Explanation:
The water we drink today is the same the dinosaurs drank because no new water has been created since. However, the cycling of water in the planet requires for it to travel from one sink to another in a process that may last millions of years. For example, the water the dinosaurs drank may have sank to the bottom of the ocean and remain there for millions of years and thus would technically not be the same that we drink today.
 
        
             
        
        
        
Answer:
A. anaerobic respiration in muscle cells, forming lactic acid
Explanation:
Running marathon is a vigorous exercise, which often leads to excessive use of oxygen in the cells of the athlete. This causes the cells to switch from the aerobic (with oxygen) to the anaerobic (without oxygen) mode of respiration. This anaerobic respiration produces a product called LACTATE OR LACTIC ACID. 
The lactic acid becomes excessive and gets stored in the muscle cells of the athlete. This often leads to cramps, muscle pulls etc. during the marathon. Therefore, an individual running a marathon may experience periods of oxygen deprivation that can lead to anaerobic respiration in muscle cells, forming lactic acid.