The muscles of the muscular system keep bones in place; they assist with movement by contracting and pulling on the bones. To allow motion, different bones are connected by joints which are connected to other bones and muscle fibers via connective tissues such as tendons and ligaments.
 
        
             
        
        
        
From  periodic  table carbon  have six  electrons nitrogen  has  seven  electrons  while oxygen  has  eight  electrons.  it s  electronic  configuration  for  carbon is 2.4, for nitrogen  is 2.5 while  that  for  oxygen is 2.6.    Their dot  diagram   are  as follows
 
        
        
        
Answer:
Suffling of genetic material increases genetic variation in offspring which is important for evolution.
Explanation:
Genetic shuffling or genetic recombination helps in the formation of new trait combinations which increase the genetic variation in the population and this genetic variation is very much important for the evolution of species.
In sexual reproduction, the genetic shuffling occurs during the formation of gametes when the two homologous chromosomes exchange their genetic material with each other. This increase variation in gametes.
Fusion of two different gametes in sexual reproduction also helps in increasing the genetic variation in the offspring.
 
        
             
        
        
        
Answer:
The answer is 3. Double Helix.