Answer:
the ability to form stable bonds
B. sexual selection, which alters allele frequencies in the gene pool.
The correct answer is muscularis externa.
The muscularis externa refers to a section of muscle in various organs in the vertebrate body, adjacent to the submucosa. It is accountable for the gut movement known as peristalsis.
In comparison to the majority of the remainder of the digestive tract, the muscularis externa of the upper section of the esophagus comprises of striated muscle. It is accountable for peristaltic movement and segmental contractions in the GI tract.
These muscles make the movement of food and churn in combination with the digestive enzymes down the GI tract. The muscularis externa comprises of a longitudinal outer muscular layer and an inner circular layer.
