This is the Prophase. 
<span>1) The chromosomes coil up and become visible while the nuclear envelope disappears. 
2) Sister chromatids are appears.
3) A centriole forms at each pole and spindle fibers made of microtubules grow out of it.
4) Short microtubules stick out from the centriole in a star shape known as an aster.
I don't remember liking biology but I do remember some things from it.</span>
        
                    
             
        
        
        
<span>Human weight at the time of birth is influenced by stabilizing selection. Stabilizing selection, also known as negative selection, purifying selection or normalizing selection, is a type of natural selection in which genetic diversity decays according to a particular value of the character. This is the most common mechanism of action of natural selection.</span>
        
             
        
        
        
When the structure and function of an organism adjusts to its environment it is adapting.
        
             
        
        
        
Answer:
The human eye is the prime organ of the body, which associates with the photons of light and allows one to see various things. The unique cells found in retina, which does activity of seeing are cones and rods cells. Rods help to see in dim light vision, while on the other hand, cone cells are unique in recognizing different colors.  
These cells comprise photoreceptor proteins that help in trapping photons at particular wavelength. Mutation in the gene encrypting for these proteins results in permanent or temporary vision issues. The extremity of defects relies upon the degree to which mutation takes place.  
The mutation in rod cells photoreceptor proteins leads to night blindness and retinitis pigmentosa. Retinitis pigmentosa refers to an inherited disorder that takes place because of early loss of rod cell, which destructs retina. On the other hand, night blindness does not mean complete blindness night, however, inadequate tendency to see in low light.  
Identically, the mutation in the cone cell also results in vision issues, known as red color blindness and tritanopia. Tritanopia refers to a kind of color blindness, which originates because of insensitivity of blue receiving protein gene towards blue light. On the other hand, red color blindness refers to insensitivity of red receiving cone cells in captivating long-wavelength photons.