A. Hydrogen ..................
Answer:
A mutation is a change in a DNA sequence. Mutations are commonly caused by mistakes during DNA replication. However, they can also be caused by ultraviolet radiation, exposure to chemicals called mutagens, and infection by viruses. But, a mutation usually occurs when a nucleotide in the DNA gets changed, causing the nucleotide sequence to be copied incorrectly which leads to the wrong code for a protein. This can sometimes be fatal.
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Answers;
Initiation of transcription;
Proteins called transcription factors are involved in the initiation stage of transcription
Explanation;
Transcription factors are proteins that help turn specific genes "on" or "off" by binding to nearby DNA.
Transcription factors that are activators boost a gene's transcription while the repressors decrease transcription.
These factors allow cells to perform logic operations and combine different sources of information to "decide" whether to express a gene
