Answer:
The reader learns that in order to survive, you have to depend on other people.
Explanation:
 
        
             
        
        
        
C.	because Buck stole some food
        
                    
             
        
        
        
 - We know the answer is not A, because you generally do not want to support meat for a vegetarian publication.
 - We know the answer is not B, because triple chocolate donuts have nothing to due with "Muscle Builders Weekly."
 - We know the answer in not C, because you are probably not looking for dating ads if you are already married.
 - The answer is D, because it is reasonable to explain pet grooming for a publication for pet lovers.
 
        
                    
             
        
        
        
The opposite of sloppily in English would be cleanly or neatly - lo contrario de sloppily en inglés sería cleanly or neatly.
        
             
        
        
        
The common idea presented in both ‘our solar system: In-Depth’ & ‘Our Solar System’ is our solar system in detail.
<u>Explanation
:</u>
Both of them talk about the solar system, the sun, and its planets, their constituents, sequence of the location of the planets in reference to the sun, their formation and significance.  
Besides the solar system, the former also talks about the Milky Way, its formation, the explosion of two supernovas that led to the formation of solar systems, and other constituents of the Milky Way - a spiral mass and our galaxy, one among many others in the big universe.
It also gives a reason behind the location of the first four planets near the sun and the gaseous and icy masses away from the sun.  
It also talks about the other masses that are there in the Milky Way like the asteroids and comets.