The correct terms to fill in the blanks would be contracts and dilates. In stressful situations, the sympathetic nervous system contracts the arteries of the circulatory system resulting to the dilation of the pupils of the eyes. Also, during these situations, the blood sugar levels are raised since the hormones for stress kick in to combat the stress which in turn raises the blood sugar.
Hydrogen bonds are weaker than covalent bonds.
Effects that scientists had predicted in the past would result from global climate change are now occurring: loss of sea ice, accelerated sea level rise and longer, more intense heat waves.
Answer:
This is through the process of methylation and phosphorylation of histones tails.
Explanation:
The addition of a methyl group to the amino acid of the histones of the nucleosomes that compacted DNA in the nucleus is called mehtylation, while the addtion of phodpahte is phosphorylation
Its effects on gene expression depends on the number of <u> methyl groups, and type of amino acid that methylated. During transcription. </u>
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The DNA double strands are compacted and therefore hidden from transcription factors and enzymes of transcription by the hitones tails of the neuclosomes, Methylation weaken the binding bonds between the tails and DNA structure ; thereby aiding the uncoiling of DNA from the tails.(nucleosomes).This chemical reaction aided DNA strands exposure to transcription factors and enzymes, for initiation of transcription. This explains the dyanmic activity of methylation
Futhermore phophorylation also favours unwrapping of DNA, by imitating modifying enzymes e.g H3Y41E and H3T45E and convert it to→→ H3Y41phopspahte to aid DNA unwrapping and accessibility to transcription factors and RNA polymerase Enzymes,
Answer:
Plants that have many periods of reprodution are called perrenials.
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