The correct answer is b each with two new strands
        
             
        
        
        
Please find the answers CAPITALIZED below.
Mercury's SURFACE strongly resembles that of EARTH's SURFACE, with very large impact CRATERS
Mercury, the second densest of all planets shares an exterior similarity with the Earth's moon. Given the rough-like exterior feature of the moon, Mercury surface is scarred by craters due to the collisions of comets and meteroids. 
        
             
        
        
        
Answer:
TCA GCC GGA I think this is right
 
        
             
        
        
        
Explanation:
In the majority of cases, the extra copy of chromosome 21 comes from the mother in the egg.
In a small percentage (less than 5%) of cases, the extra copy of chromosome 21 comes from the father through the sperm.
In the remaining cases, the error occurs after fertilization, as the embryo grows.