Answer:
Option A, They have enzymatic properties that can covalently modify DNA.
Explanation:
Histones have very basic nature and possess no enzymatic properties. However, any modification of DNA is carried out after the end of translation process with the help of enzymes on the N –terminal tails through processes such methylation, acetylation, citrullination, phosphorylation.
There are several Histone-modifying enzymes in the human genome that interact with the non-histone proteins to form functional complexes
Hence, option A is correct
The answer is spin.
Each quantum number that describes the two electrons in a helium atom is identical, except for the one that indicates their spin.
This can affect the organisms living there because now, their environment is probably different than what they have been living in for a long time, so now they have to adapt to this new environment, and if they don't, the organisms will probably end up dying.