<span>When someone is vitamin B12 deficient, one of the reasons could be that the person’s digestive system (intestine) is not absorbing the vitamin efficiently.
Vitamin B12, also called cobalamin, is a water-soluble vitamin that is essential for the normal functioning of the brain (it participates in the synthesis of neurotransmitters), the nervous system (it is essential for maintaining the integrity of the nervous system and especially the sheath myelin that protects the nerves and optimizes their functioning) and the formation of blood (helps with the division of erythroblasts). It is one of the eight B vitamins. It is normally involved as a cofactor in the metabolism of each of the cells of the human body.
Dietary vitamin B12 is absorbed through a multi-step process. In the acidic environment of the stomach, it is separated from the food substrate of animal origin by gastric pepsins. It then binds to salivary R proteins from which it is released in the duodenum under the effect of pancreatic proteases. It can then associate with the intrinsic factor, a binding glycoprotein secreted by the parietal cells of the stomach. Vitamin B12-intrinsic factor complex travels throughout the small intestine before being absorbed in this form into the ileum via the cubam receptor. </span>
<em>If we are looking for what takes up 25% of the graph, that would be the last option. If you look at G1, it takes up about 50%. So</em>, G1 phase and M phase <em>would take up more than that, and we want 25% not 50+. The </em><em>M phase and S phase</em><em> would take up about a third, so no. The </em><em>G2 phase and M phase </em><em>takes up roughly 25% or, it's the closest to this.</em>
Both mosses and ferns undergo alterations of generations. ... The gametophyte is prominent is mosses, but the sporophyte is prominent in ferns. The sporophyte of ferns is differentiated into true leaves, stem, and roots. In contrast, mosses lack true leaves, stem or roots.
Convergent boundaries are areas where plates move toward each other and collide. These are also known as compressional or destructive boundaries. Subduction zones occur where an oceanic plate meets a continental plate and is pushed underneath it. Subduction zones are marked by oceanic trenches.