2, because a theory is not a law that can not be changed, and new evidence can change a theory.
Suppose that part of an amino acid sequence of a protein changed from tyrosine-proline-glycine-alanine to tyrosine-histidine-glycine-alanine. This change was most likely caused by a point mutation called a <u>substitution</u>.
<u>Explanation:</u>
Any protein is synthesized by joining a number of amino acids together. This amino acid is placed based on the sequences of the DNA , for every 3 sequence there is an amino acid that is synthesized and therefore it is called as a triplet codon, since there may be many sequence for a single amino acid we call it as degenerate codon.
The answer is Arteries
Arteries carry oxygen-rich blood from the heart to capillaries. On the contrary, veins carry blood without oxygen from the capillaries to the heart.
Arteries are very flexible and yet strong blood vessels so that efficient transport of oxygen-rich blood along the bloodstream through the organism is enabled.