Ans.
Chromatin molecules are made up of DNA and histone proteins. Modification of chromatin structure include covalent, post-translational changes in histone proteins, present in chromation. Acetylation and methylation are two important histone modifications that affect structure of chromatin molecules.
Acetylation involves addition of an acetyl group to histones that increases transcription of DNA by loosen the association between DNA and nucleosome.
Methylation involves addition of a methyl group to histones that results in condensation of chromatin molecule and thus, decreases transcription of DNA.
Both acetylation and methylation are reversible processes.
Many chromatin modifications are genetic, means they can pass from one generation to another generation, called epigenetic modifications.
Thus, options B), C), D), E), and F).
A physicist term for the measure of the amount of disorder is ENTROPY.
Answer:
The correct answer is - loss of soil moisture east of mountain ranges.
Explanation:
Air or wind with moisture moves towards the top of the mountains where it precipitates and condenses before crossing the mountains and when this air crosses there is no moisture left in them to precipitate on another side.
The other side called rain shadow and is forced to become the area desert in the long run which is called the rainshadow effect. The major effect of the rainshadow effect is the formation of the deserts in a natural way.
