Why are mutations that alter the amino acid sequence usually harmful?

This probably because they destroy a given character or give rise to a new one.

Explanation:

Alteration here are the permanent changes found in the DNA structure. And are totally inheritable. An example is the case of sickle cell anaemia and haemophilia. People with this anaemia trait hardly live and reproduce even though they do not show ill effects.

Therefore, this mutation alteration is harmful because they destroy a given character.

Answer: The give alter initial amino acid sequence.

Explanation:

Mutation is sudden heritable change in DNA sequence it can be inherited from parents by offspring. When mutation affects DNA sequence it could bring about deletion of important base sequence, insertion of new base sequence or frameshift leading to formation of entirely new base sequence and amino acid. This new sequence is a mutation and it could give rise to abnormalities in the body system. Evolutionary changes is as a result of accumulation of mutations, aneamia is also an example of mutation in human.