Weathering is the process by which rocks are broken down into smaller particles as a result of physical and chemical changes that are occurring in them. There are three major types of weathering these are: physical, chemical and biological weathering.
For the question given above, the type of weathering that is occurring in the picture of the given rock is PHYSICAL WEATHERING.
Physical weathering is the type of weathering in which the affected rock is changed in size and shape by means of some agents. The broken particles are usually of the same composition as the parent rock. The agents of physical weathering include: ice, plant roots, animal activities, abrasion and exfoliation. Physically weathered rocks are usually round in shape as a result of the abrasion process which they have undergone.<span />
Answer:
A. The chromatin near cis-regulatory sequences will be more closed and there will be less transcription.
Explanation:
In the presence of histones, the cis-regulatory sequences of DNA like promoter, enhancers etc. are not exposed. The function of the histone acetyltransferases (HATS) is to cause chromosome decondensation i.e. removal of histones from the DNA so that transcription of the DNA could occur. Histone acetyltransferases (HATS) cause acetylation of lysine amino acid of the histone proteins. Acetyl group is negatively charged so the acetylation of histone proteins leads to the removal of their positive charge which ultimately leads to the decrease in the interaction between N terminal of histones and negatively charged phosphate group of the DNA molecule. As soon as histones are removed from the DNA where cis-regulatory sequences are located, the DNA becomes accessible for transcription.
But here a drug has been added which blocks the activity of histone acetyltransferases (HATS) in cancer cells. So it is quite evident that in these cells, histones will not get removed from the cis-regulatory sequences of DNA so the DNA will be more closer or tightly packed as a result of which less transcription will occur.
Human exploitation of fragile ecosystems can lead to the droughts and arid conditions characteristic of desertification. Effects include land degradation, soil erosion and sterility, and a loss of biodiversity, with huge economic costs for nations where deserts are growing.