Answer:
macroevolution
Explanation:
Macroevolution is said to be the evolutionary changes that occur on a larger scale beyond a single species as a result of evolutionary forces such as mutation, gene flow, genetic drift. Macroevolution, unlike microevolution, usually results into the emergence of two new species with pronounced changes. The event as illustrated in the question is an example of macroevolution.
 
        
             
        
        
        
The first three are the same as those found in DNA, but in RNA thymine is replaced by uracil as the base complementary to adenine. This base is also a pyrimidine and is very similar to thymine. Uracil is energetically less expensive to produce than thymine, which may account for its use in RNA.
        
             
        
        
        
Distance is the length of the path travelled
displacement is the shortest length of the path travelled
distance does not have direction, hence, it is a scalar quantity
displacement has direction, hence, it is a vector quantity
        
             
        
        
        
Answer: What is expected to happen is that the secondary immune system acts immediately against the virus.
Explanation:
When a virus first enters our body, in order to defend itself, the body must first recognize what the antigen is in order to fight it through <u>antibodies</u>. Once it does it will keep a memory of it that it can use if this virus enters the body again. <u>This will be done through the secondary immune system</u>.
As the body already recognizes the antigen, it knows how to fight it immediately, generating a thousand times the amount of antibodies generated the first time.
Thanks to its memory cells, the virus will remain much less time in the body.
 
        
             
        
        
        
El Niño as evidence of potential dangers of global warming to marine ecosystems
Explanation:
El Nino, an abnormal type of weather pattern, causes huge climatic variations globally by bringing floods in one region and drought in another region. These extremely changing patterns in weather can damage human life, agriculture, air quality, natural ecosystems, etc all of which might lead to global warming.  
El Nino effect is a serious potential danger to the marine life. This causes variations in the sea surface temperature, ocean currents, and upwelling patterns. Due to this, many marine organisms either migrate to newer places or do not survive the change. 
Due to this, other sea animals depended on them also are depleted of their food source. El Nino also impacts the structure of coral reefs causing coral bleaching which in turn affects the marine life.