Answer:
A cell membrane is made of two layers.
The cell membrane is composed by a phospholipid bilayer where the interior side is hydrophobic and non-polar, while the outside is hydrophilic and polar
Pores and proteins in the cell membrane allow passage through it.
The pores and proteins in the cell membrane have several functions such as, for example, cell signaling (proteins) and selective transport (pores)
Echinoderms, like chordates, are deuterostomes and are therefore thought to be the most closely related of the major phyla to the chordates
