There are differences between Eukaryotic and Prokaryotic cells. This difference is considered to be the most important distinction between groups of organisms. A Prokaryotic cell does not contain a nucleus. It only contains one chromosome and is a single-celled organism. It was the only form of life on earth for millions of years. Examples of a Prokaryotic cell are the different types of bacteria present today. 
A Eukaryotic cell contains a nucleus; more than one chromosome and is typically a multi-celled organism.  <span>Both plant and animal cells are eukaryotic cells.</span>
        
             
        
        
        
Human encroachment that has greatly reduced the prairie dog populations.  
        
                    
             
        
        
        
Answer:
The correct answer is B. Worms move through changes in body structure caused by contraction of muscles compressing their watery fluid.
Explanation:
The hydroskeleton consists of a fluid-filled cavity, surrounded by muscles. The fluid pressure and the action of the muscles that border it, serve to change the body's shape and produce a movement such as digging or swimming. The successive contraction of various metamers, which are provided with bundles of circular and longitudinal muscle fibers, stretching and thickening parts of the body, allow it to move horizontally. Hydrostatic skeletons have a role in the locomotion of annelids, nematodes and other invertebrates. The hydroskeleton has similarities with the hydrostatic muscles.
 
        
             
        
        
        
Answer: Eagles mate sexually.
Explanation: Typically the male eagle mounts and humps the female eagle.