1 Collagen is most commonly found within the body in the skin, bones and connective tissues. 2  The word collagen is derived from the Greek kolla, meaning glue.  Collagen gives the skin its strength and structure, and also plays a role in the replacement of dead skin cells.
sieve A sieve is a mesh strainer used to separate lumps and clumps from the fine material. Sieves are handy for everything from sifting flour to prospecting for gold â anything where you need to separate the big from the small. If youâre an archaeologist, you've probably used various sorts of sifters and shakers to sieve through the soil to recover even the tiniest artifacts.
Definition of sieve-tube element : a thin-walled elongated living cell that has no nucleus at maturity, is continuous with other similar cells by protoplasmic strands which pass through the perforations of specialized sieve plates, probably functions primarily in the translocation of organic solutes, and is the basic element of the sieve tube â compare sieve cell