*The rate at which radioactive decay occurs.
*How much radioactive decay has occurred.
        
                    
             
        
        
        
Hey there what is your question?
        
             
        
        
        
A cycadophyta is a biological dividsion, and within this,nthree are three families, and these are; Cycaclaceae, Strangeriaceae and Zamiceae. The plants of these are seed plants, which generally have characteristics, such as a stout, short and tough trunk made of wood, with a crown like span of evergreen leaves, with a cone shape protruding from the centre of the tree.
Sorry, I wasnt able to attach an image, but if you google cycadophyta, this is what they look like.
Sorry for the inconvenience, hope this helps
        
             
        
        
        
One of the difference is that fishes have single circulation but humans have double circulation of blood.