Answer:
C) Through genomic imprinting, methylation regulates expression of the paternal copy of the gene in the brain.
Explanation:
The pattern of gene expression wherein either paternal or maternal gene is expressed in specific cells while the other one is prevented from expression is known as genomic imprinting.
In the given example, the maternal copy of the gene on chromosome 15 is expressed in brain cells while its paternal copy is not expressed in these cells. Hence, the pattern of expression of this gene is regulated through genome imprinting. One of the mechanism is methylation of cytidine residues of CpG islands of the DNA that are more frequently present within promoters of the genes.
When the cytidine residues of these sequences are methylated into 5-methylcytidine, the transcription factors do not bind to these promoters preventing the expression of these genes.
Hence, methylation of cytidine residue in CpG islands of the promoters of the gene present on chromosome 15 could have silenced its expression in brain cells.
I would say that B) single events or several causes working together to produce extinction in a short period is referred to as mass extinction, but I am not 100% sure.
Answer:
Calories
Explanation:
Calories provide the body with energy that it needs. Everyone needs to consume a certain number, but each person’s needs are different based on their body and activity level.
Because the earth's is roughly spherical the sun's light is distributed over a wider area towards the poles, so it has less heating effect... the air cools and falls over the poles and returns to the equator close to the ground. This assumes that there is no other effect (e.g. wind, low or high pressure regions etc.)
