The trait must no longer be essential to survival or it's purpose has decreased over time.
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Answer:
The correct answers a and b.
The inheritance of Becker and Duchenne dystrophies are linked to the X chromosome.
Explanation:
Duchenne and Becker muscular dystrophies (DMD and BMD, respectively) are neuromuscular diseases characterized by progressive muscle atrophy and weakness, as a consequence of the degeneration of skeletal, smooth and cardiac muscles. Both muscular dystrophies are caused by mutations in the DMD gene, located on the X chromosome. This is the largest known human gene and it encodes a protein called dystrophin, which is expressed in muscle cells. The mutations responsible for DMD lead to a total absence of dystrophin, while those underlying DMB lead to an abnormal quantity and / or quality of the protein. In both cases it is common to find deletions of the gene.
A Parfocal microscope helps in see object accurately
The answer to the given question will be that the muscles that guard the entrances and exits of the internal passage are known as sphincter (circular muscles).
- Due to their structure and controllability, skeletal circular muscles differ from their smooth muscle counterparts.
- The muscularis mucosa, which is mostly found in the stomach, is composed of smooth muscle.
- The longitudinal layer shortens the tract while the circular muscle layer in the muscularis externa prevents food from moving backward.The human body contains at least 50 or 60 different types of sphincters.
- Some are quite small, like the many precapillary sphincters that line the circulatory system's blood vessels.
- Lower esophageal sphincter (LES), pyloric sphincter (PS), ileocecal sphincter (ICS), and internal sphincter are the four different smooth muscle sphincters found in the GI system (IAS).
Hence, the answer is that the muscles that guard the entrances and exits of the internal passage are known as sphincter (circular muscles).
Learn more about muscles here:
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According to the phylogenetic tree, Eukarya evolve <u>First in the Prokaryotic Organisms.</u>
