20.58 by using a calculator you can determine this, then round
<u>Halogens are reactive because:</u>
They have high electronegativity and also high nuclear charge. So, they are reactive and also gain an electron when they react with other elements.
Since they are very reactive, halogens are very harmful to living organisms. Some of the halogens are fluorine, chlorine, bromine, iodine, astatine. These are mostly non metals. Fluorine is one of the most reactive gas and also very toxic gas. When Fluorine reacts with glass along with small amounts of water, it forms silicon tetra fluoride (SiF4). Hence fluorine should be handled with substances like the inert organofluorine compound Teflon.
The lac repressor protein binds to the operator when it is active. The lac repressor is a protein or a DNA-bounding protein as it is called. The lac repressor also involves the lactose metabolism and it is also responsible for the transcription of three lac genes.
Its 4.08 i hope hopefully its helpful
