The network of fibres present in the cytoplasm of a eukaryotic cell is called cytoskeleton. The cytoskeleton is of three types.
a) The three cytoskeletons are microtubules, microfilaments and intermediate filaments.
b) Microtubules are cylindrical fibres and are made of tubulin protein, microfilaments are thread-like protein fibres made of actin protein and intermediate filaments are made of different types of proteins, among them keratin is the main protein.
c) Microtubules determines the shape of the cells, microtubules are associated with contraction of muscles and intermediate filaments provide tensile strength for the cell.
The function of the limb is to help them get around and move. They might be similar in the way they’re structured? I don’t have a picture so I can’t tell. And you can assume that at one point these four animals all shared a common ancestor. Hope I helped!
