Crossing over occurs at the four-strand stage when two homologous chromosomes, each consisting of a pair of sister chromatids, are paired. Each crossover involves just two of the four strands and generates two recombinant strands.
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Answer: in order from small intestine to the rectum: 1, 4, 2 and 3.
Explanation: Ascending colon; the colic valve(the ileocecal valve) is located at the bottom of the ascending colon. At the top of the ascending colon, the colon bends to the left, forming the right colic flexure called the hepatic flexure. The transverse colon begins after this flexure.
The transverse colon; is the longest and most movable part of the colon which runs across the abdomen from the ascending colon at the right colic flexure with a downward convexity to the descending colon, here it curves abruptly on itself under the lower end of the spleen to form left colic flexure called the splenic flexure.
Descending colon; it start from the splenic flexure to the beginning of the sigmoid colon. The descending colon stores the remnant of digested food that will be deposited into the rectum.
Sigmoid colon; also known as pelvic colo is the closest to the rectum, it is a passage by which digested food move into the rectum.
Answer:
structures that preform many jobs in cells :)
