Please rephrase the question, it doesn't make sense.
        
             
        
        
        
Answer:
Explanation:
1) Excitation brings about contraction.
2) Contraction leads to an increase in blood pressure. 
3) Changes in blood pressure results in the opening and closing of the heart valves.
4) The opening and closing of heart valves then regulates the flow of blood and it's volume.
 
        
             
        
        
        
Answer:
The correct answer would be option D.
Explanation:
True breeding is a breeding procedure in which the parents would always produce their progeny with the same phenotype characters as the parents carry. This means for every trait these parents are homozygous so their offspring must show a similar phenotype.
In this case, all cattle are true-breeding which means they homozygous alleles show the progeny will also show similar traits which are short stature with brown hides and short horns.
Thus, the correct answer is option D.
 
        
             
        
        
        
Answer:
1. Aqueous solutions of acids are electrolytes, meaning that they conduct an electrical current. 
2. Acids have a sour taste. 
3. Acids change the color of certain acid-base indicators. 
4. Acids react with active metals to yield hydrogen gas.
Explanation:
I looked it up.
 
        
             
        
        
        
Through the atmosphere and through <span>oceanic conveyer belts that act as physical pumps</span>