Ans.
HD (Huntington's disease) is a genetic neurological disorder that occurs due to damage and death of brain cells. it is caused by an autosomal dominant mutation in HTT (huntingtin) gene, having a trinucleotide repeat section that makes HTT protein.
The mutation leads to an increase in this nucleotide repeat count, associated with formation of altered or mutated huntingtin protein. These altered proteins show deleterious affect on brain cells and result in Huntington's disease.
Thus, the correct answer is 'option A). a mutated gene.'
<span>If a nurse uses just a wet paper towel to turn off the taps on the sink after washing, she will likely contaminate the surface of sterile items. This is not the proper procedure or protocol, and can make sterile items unsafe and dangerous due to bacteria and spreading of illnesses.</span>
Biosphere. Bio means life, and Biosphere means ALL life on earth.
The environment is your correct answer<span />