Most likely to be A which is probably an artery which carries blood away from the heart Nd tens to carry oxygen rich blood
the leg doesnt contain aveoli this is found in the lungs so its not B
since its oxygen rich little carbon dioxide will be present in this structure so its not C
this part cant be part of the respiratory system as the respiratory system includes lungs, mouth and etc but not the legs so it cant be D
hope that helps
Significance of the birds in the old man
Answer:
Generally proteins are denatured at high temperature.Therefore when the egg is hard boiled they are denatured since eggs are protein, the 3-dimensional structure of protein is lost, and it is replaces with tangled meshwork of polypeptide chains .This is because the orderly arrangements of disulphide bonds in proteins are disrupted , which results in the formation of inter chains bonds among disulphide bonds, making the protein molecules to link together.This explains the reason for the 3-D structure disruption and formation of a macro molecule.
However, the addition of reducing agent , breaks the covalent disulphide bonds. While detergent breaks the interchain bonds among the disulphide bonds. (The noncovalent bonds),These combined effects untangled the mesh networks of polypeptides formed, and reduces the hardened nature,
Explanation: