The doctor removed the duodenum from the body.
This is an example of vestigial structure.
Vestigial structures are structures (cells, tissues and organs) found in an organism that has lost most or all of its primitive function through evolution. The vestigial structure has performed vital functions in the organism in the past but as there are changes in species as a result of natural selection, the structure became less important until it no longer functions. A reduced nonfunctional digit on the paws of dogs known as a dewclaw is an example of vestigial structure.
The event order should be:
1. Ingesting food, the small bowel filled with food solutes and become hypertonic. It will attract water from the blood which is hypotonic
2. Food digested, some of it absorbed. The osmotic pressure inside bowel will be reduced.
3. All food is absorbed, the osmotic pressure reduced significantly makes it hypotonic. The blood attracts water as it is hypertonic. This will increase the blood volume
D to help the organism to reproduce
Answer: The tension is relieved by an enzyme named topoisomerase
Explanation:
As replication starts DNA polymerase needs to move forward of double strand DNA, this creates a lot of tension in the DNA molecule. The tension is relieved by the action of an enzyme named topoisomerase. The stress relieve is needed for the progresion of the replication mechanism.
There are to types of topoisomerases:
a) Topoisomerase I
b) Topoisomerase II
Topoisomerase I underwinds the DNA double helix by making a single cut in one of the strands of the DNA molecule. Once the cut is made, the DNA unwinds and torsional stress is released. Finally the DNA strand , that was cut is ligated ( see attached image)
Topoisomerase II acts when torsional stress is made because two DNA strands cross each other (superhelical stress). Topoisomerase II cuts both strands of a DNA molecule. After this cut is made the DNA unwinds and torsiona stress is relieved ). Finally both DNA strands are ligated ) see attached image)
Topoisomerases II enzymes require ATP hydrolysis to perform the cut of both of the DNA strands.