Answer:
Population- This is why we refer to the amount of people in an area as the area's population
 
        
                    
             
        
        
        
1. bony fish
2. cartilaginous fish 
3. jawless fish 
4. cartilaginous fish 
5. bony fish 
6. cartilaginous fish 
7. Jawless fish 
8. bony fish
9. cartilaginous fish 
10. bony fish
        
             
        
        
        
They have different types of cell walls and cell membranes. 
 
        
                    
             
        
        
        
Proteins attract water and hold it within blood vessels, preventing it from freely flowing into the spaces between the cells. This is an example of how protein is used for maintaining fluid and electrolyte balance.
<h3>What is Protein?</h3>
- Large biomolecules and macromolecules known as proteins are made up of one or more extended chains of amino acid residues.
- Among the many tasks that proteins carry out in living things include catalyzing metabolic processes, replicating DNA, reacting to stimuli, giving cells and organisms structure, and moving molecules from one place to another. 
- The primary way that proteins differ from one another is in the order of their amino acids, which is determined by the nucleotide sequence of their genes and typically causes a protein to fold into a certain 3D structure that controls its activity.
<h3>What Constitutes Proteins? </h3>
- Amino acids, which are tiny chemical compounds with an alpha (central) carbon atom coupled to an amino group, a carboxyl group, a hydrogen atom, and a variable component known as a side chain, are the building blocks of proteins.
Learn more about Protein here:
brainly.com/question/17095120
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Answer:
The principal difference in development of Dorsoventral axis in deuterostomes and protostomes is something called inversion
Explanation:
In protostomates the neural tube is below the gut and the dorsal vessel is above the gut while in deuterostomates is the oppossite, there is an inversion and now, the neural tube is above the gut and the heart tube is below. In both cases the development is related to the gradient of expression of some genes, where the expresion of one gene supress the formation of one structure in one side of the axis.
In protostomates the TGT-B factor is expressed dorsally and supress neural tube formation and ventrally a sog gene is expressed and supress TGT-F factor allowing neural tube to develop. In deuterostomates, an homolog of TGT-B family gene BMP-4 is expressed ventrally while dorsally BMP inhibitors (sog gene like) are expressed.
Accordingly to some researchers, the first state of the common ancestor of deuterostomates and protostomates had an protostomate-like orientation in dorsoventral axis