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

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 substitution.

Explanation:

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.

estuaries are the partially enclosed coastal bodies of brackish water formed at the mouth of sea where river meets an ocean. it is a transition zone between river and sea water so estuaries are influenced to both marine environment such as tides, waves and to riverine such as flow of fresh water and sediments. the mixing of sea and fresh water provide high level of nutrients, making estuaries a high product habitats.

many estuaries suffers degradation from a variety of human activities like erosion from deforestation, overgrazing, overfishing, drainage and eutrophication.

so from the above statement answers will be

1. false as estuaries are formed due to both brackish and freshwater.

2.true, due to high productivity estuaries are breeding ground for many marine species.

3. direct and indirect activities of man that contribute to pollution and deposition of sediments.