The body wall<span> of a star fish is made up of a thin cuticle, an epidermis with a single layer of cells, a thick dermis composed of connective tissue and a thin coelomic myoepithelial layer, which allows the longitudinal and circular musculature.</span>
 
        
             
        
        
        
Answer: When using fossils approximate age by comparing it to similar rocks and fossils of known ages, is called relative dating. 
Using that method we can determine the age of rock layers. That’s our way of dating them. 
Hope this helps! ^^ 
        
             
        
        
        
You need organisms like some are in plants and without Plants how will the animals eat
        
             
        
        
        
The effect of geographic isolation is that the two populations are subjected to different selection (pressures) and geographic conditions. The conditions in the two areas, if different, will produce different alleles in that species and will be selected for, where genetic differences will gradually accumulate between the two different populations.
In time, enough genetic differences will occur so that the two populations will no longer interbreed. Then, by definition, they have become different species.