There are around 350,000-600,000
        
             
        
        
        
Answer:
They are genetically identical to the parents and only differ if a genetic mutation occurs.
Sexual reproduction involves two parents and produces offspring that are genetically unique.
The greater the genetic variation, the better change that an individual in the population have a favorable gene that can help survival.  Genetic variation is an important force in evolution as it allows natural selection to increase or decrease frequency of alleles already in the population.
Explanation:
 
        
             
        
        
        
Answer:
Our body cells require oxygen to release energy.
Explanation:
The oxygen that we take in during respiration is used to break down the food we eat to release energy from it. When we breathe in oxygen, it diffuses into blood from the lung, where it is transported by red blood cells to the entire body to be used to produce energy.