Answer:
Sigma factors bind to the promoter region of a particular gene and facilitating the binding of RNA Polymerase to the promoter region (formation of the RNA polymerase holoenzyme complex) in order initiate transcription of the gene.
Put simply - Helps RNA Polymerase do it's job.
Answer: No, mRNA ( messenger RNA) model does not closely resemble the DNA strand from which it is transcribed.
This is because mRNA strand is complementary to the strand of DNA template that is used in its synthesis during the process called transcription. The polarity of DNA template is 3' to 5' whereas that of mRNA transcribed is 5' to 3' that is both the strands have antiparallel polarity.
This is the reason template DNA is referred antisense. mRNA strand more closely resembles the sense strand ( which is complementary strand of DNA template in a double helix).
1. Limited energy supply to other organisms
2. Herbivores will be scarce because they don’t mate
3. Avoid pollution
Adding sanctions and punishing offenders
Biology helping with medical research and treatment