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The five processes in the nitrogen cycle – fixation, uptake, mineralization, nitrification, and denitrification – are all driven by microorganisms.
Answer:
Fight or flight response.
Explanation:
Fight or flight response is also known as hyper arousal response. This response is mainly generated in case of attack and harmful event.
Jade hears a rattle sound and sees a rattle snake as she turns turns around, this is a type of harmful event or fear for Jake. This condition causes the dilation of pupil, sweat and heart pounds in Jade's body. The fight and flight response has been generated in Jade's.
Answer:
a) i. low, ii. high, iii. low
Explanation:
Answer:
a. Biomagnification
Explanation:
Biomagnification is the name given to the progressive accumulation of substances from one trophic level to another along a food chain. Thus, the substance will have its highest concentration in individuals who occupy trophic levels furthest from producers.
For biomagnification to occur, substances must be fat soluble (lipid soluble) and thus adhere to living tissues. Another feature of substances that undergo biomagnification is that they are generally not biodegradable or metabolized by the body.
The phenomenon is quite common with heavy metals (lead; mercury) and certain chlorinated and aromatic organic compounds with higher molecular mass, such as the insecticide DDT.
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.
