Because they take up both parts of traits so that makes it group to similar organisms
Explanation:
Central dogma represents the pathway in which the information encoded in the DNA flows into proteins.
The DNA is made up of the nucleotide monomers in which the nitrogenous bases are present as one of the constituents. These bases are present in the sequence are transcribed into the RNA molecule through the process of transcription.
The nitrogenous sequences in this RNA molecule are then translated into the proteins through the process of translation during which the sequence is read in pairs of three called "codons". A specific amino acid is attached to the peptide when the codons are read by the translation machinery and a protein is formed.
These proteins could perform various roles in organisms from physical to biochemical and thus the physical traits are controlled by the DNA.
Both seta and cheta or chaete means bristles. I think the term can be used interchangeably . Just check this link:- http://en.wikipedia.org/wiki/Polychaete It about polychaetes a class of annelid worms. These are extracts form the passage:- Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called *chaetae, which are made of chitin. Indeed, polychaetes are sometimes referred to as bristle worms. Bundles of bristles, called *setae, project from the parapodia. http://en.wikipedia.org/wiki/File:Polychaeta_anatomy_en.svg Thats a cross section the terms have been used interchangebly.
<span>A planulae is not one of the three major structures of coral reefs as it is one of the stages in the life cycle of a jellyfish known as the free swimming larvae stage.
Coral reef structures are made up of fringing reefs that grow directly from the shore,
atoll reefs that grow upward usually in a lagoon, and barrier reefs are separated from the land and shore by open water.</span>