Answer:
The correct answer is None of these choices are correct.
Explanation:
Crossing over doesn't occur only between heterozygous genes, it also doesn't happen only in some chromosomes and it never reduces de variation, otherwise, the crossing over is one of the main causes of variation among species. 
 
        
                    
             
        
        
        
Statement D best describes the difference between the way plants and animals obtain energy.
 
        
                    
             
        
        
        
Answer:
A. As a young naturalist, Charles Darwin traveled around the world and made many discoveries on a small British navy ship, HMS Beagle.
 
        
                    
             
        
        
        
Answer:
Sunlight and water.
Explanation:
The sun is the plant's most important nutrient. Plants convert sunlight into sugars in order to grow. Water is needed in two ways, it serves as both a solvent for mineral salts that are carried inside plant cells, and it is an essential component of photosynthesis. The questioner might have asked "name one" so they don't have enough information to answer with any greater certainty - but the answer remains the same regardless of how many nutrients they ask about.
Minerals are also required by plants in order to function properly including calcium, potassium, iron, magnesium just to name a few minerals which are found in healthy nutritious produce!