The right answer is D.
The absorption of molecules at the level of the skin is carried out by passive diffusion for the molecules of low molecular weight (lower than 400 Da), the skin being covered with a lipoprotein film rich in water by its stratum corneum, rendering it little-permeable.
This absorption may be variable according to factors related to the skin such as stratum corneum's thickness, the state of hydration, the presence of cutaneous lesions or individual variations.
External factors may also modulate percutaneous absorption such as contact time, iontophoresis or the presence of specific adjuvants.
Cell wall - Adds structural support to the cell. Holds the cells together
Cell membrane - Serves as a barrier to the cell and allows more nutrient and molecules to move in and out of the cell without letting things that can harm the cell in.
Outer membrane - Serves the same basic functions a the cell membrane. (Depending on how complicated the class your in is, I would visit this website for more information... https://en.wikipedia.org/wiki/Bacterial_outer_membrane )
Pili - Help the cell move and attach the bacteria to surfaces are other cells.
DNA - Contains the genetic instructions on what the cell can physically do, operate, and reproduce.
Flagellum - Helps the cell move. It kind of acts like a propeller for the cell so that it can move around.
<span>A point mutation that results in the substitution of one amino acid for another within a protein is a missense mutation.
</span>This type of mutation<span> is a change in one DNA base pair that results in the substitution of one amino acid for another in the protein made by a </span>gene<span>. </span>
C is the answer
:) for your question (im writing extra cause answer is too small)
Collagen is a substance that is made up of amino acid linked together to form long, branched polypetide (tertiary protein chains). Thus COLLAGEN is the protein.
