Answer:
a) Teeth arose from the rough scales of ancestral sharks.
b) Skeletal developments leading to the amphibian movement onto land probably evolved from lobe-finned fishes.
d) The anterior gill arch formed the basis for the evolution of the vertebrate jaw.
Explanation:
The animals we know today have physical characteristics that are evolutionary adaptations of characteristics of their ancestors, which have undergone a series of evolutions and modifications over the years giving rise to new species that have resulted in the species we know today. This process of evolutions and adaptations also happened with the ancestral species of fish, which allowed that today, they had characteristics such as teeth and jaws. Many of these evolutions occurred even in different species, such as the evolution that allowed the amphibians to have a skeleton, which evolved from the spine fins of fish.
 
        
             
        
        
        
46 
hope this helps:)sorry if it doesnt
 
        
             
        
        
        
The answer is going to be the letter D, nitrogen. I hope this helps!!
        
             
        
        
        
If you're asking what 'controls' the cell, then that would be the nucleus. The king of the cell.