<span>s that a single on off switch can control the whole cluster of functionally related genes; these genes are coordinately controlled (ex: when Ecoli must make tryptophan for itself because the nutrient medium lacks this amino acid all the enzymes for the metabolic pathway are synthesized at one time)</span>
I think the answer is C. lower pressure
Answer: It is True species richness grows twoards the poles
The answers are;
The muscular contractions are wave-like
The muscular contractions are entirely involuntary
This action is called peristalsis.
It is powered by the expansion and contraction of the smooth muscles present in the esophagus. It is controlled by the sympathetic activity of the autonomic nervous system hence
the movements are involuntary.