Answer:
Stephen Stearns states that natural selection doesn't mean the survival of the fittest organisms, but rather this mechanism is illustrated by the selective reproduction of the fittest. Natural selection can be classified into distinct types, including directional, disruptive and stabilizing selection, which are in turn based on sexual selection. These types of selection are driven by different outcomes that have different dynamics.
Answer:
The Cell Membrane
Explanation:
Eukaryotic Cells are membrane-bounded, Prokaryotic cells are not.
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Answer:
Pretty sure they're both A.
<h2>The given statement is true</h2>
Explanation:
Iron absorption occurs in the duodenum and upper jejunum of small intestine
- At physiological pH ferrous iron is rapidly oxidized to the insoluble ferric form
- Gastric acid lowers the pH in the duodenum which enhances the solubility and uptake of ferric iron
- Once iron gets inside the enterocyte it can be stored as ferritin;Ferritin is a hollow spherical protein which helps in storage and regulation of iron levels within the body
- Ferritin molecule have ferroxidase activity which helps in the mobility of Fe2+ out of the enterocyte by ferroportin
- Transferrin is the major iron transport protein which transports iron through blood
- Fe3+ binds to transferrin so Fe2+ transported through ferroportin must be oxidized to Fe3+
- Fe2+ needs to be oxidized first so that it can be transported through ferroportin
- Once iron gets inside the cell it can be used for various cellular processes
