The double-helix shape of DNA.
All of these are necessary
Your cardiovascular system is what moves blood through your body, delivering oxygen, nutrients, and more to its many cells. Those veins and arteries keep you alive. In your home, there are pipes that deliver water to different rooms of the house, helping you stay clean and hydrated.
Activators and repressors are transcription-control elements that are found in eukaryotic organisms. These elements function during the process of transcription, where a DNA molecule is coded onto a RNA molecule for it to be sent to ribosomes outside of the nucleus and then polypeptide chains are produced from it.
The activators and repressors control which proteins are made, which means that they can either hinder or promote certain functions in the cells of the body. Therefore, even though all of the cells have the same set of DNA, some are able to produce HCl, while others produce other substances such as insulin.
