Amino acids contain a acidic carboxylic acid group connected to their alpha carbon.<span> The alpha carbon is also connected to an amine group and an R group that is distinct to each amino acid.</span>
Microtubules are one of the cytoskeletal filament systems in eukaryotic cells. The microtubule cytoskeleton is involved in the transport of material within cells, carried out by motor proteins that move on the surface of the microtubule.
Hope this helps you!
The second stage of prenatal development begins at about two weeks after conception. at this point, the growing bundle of cells is called an embryo.