There are three main types of galaxies<span>: Elliptical, Spiral, and Irregular. Two of these three </span>types<span> are further divided and classified into a system that is now known the tuning fork diagram. When Hubble first created this diagram, he believed that this was an evolutionary sequence as well as a classification.</span>
        
             
        
        
        
Meiosis - the cells divide to produce 4 haploid cells 
 
        
             
        
        
        
Cholera develops when the bacterial toxin prevents G-protein inactivation , which leads to the continuous production of cAMP.