Collagen is a part of the connective tissue that in the skin helps in firmness, suppleness and constant renewal of skin cells. Collagen is vital for skin elasticity. Ligaments are another type of connective tissue that attach two bones and consequently hold the joints together.
There are at least 33 phyla (plural of phylum) of animals. Humans are members of the phylum Chordata. All of the chordates have elongated bilaterally symmetrical bodies. That is to say, the left and right sides are essentially mirror images of each other.
(October 2010). Human taxonomy is the classification of the species Homo sapiens (Latin : knowing man), or the modern hominin, humans. Homo, the human genus, includes the past genetic tree of humanity, with Neanderthals, Denisovans, and other extinct species of hominin.. sapiens is the only surviving species of the genus Homo. Extinct Homo species include archaic humans. Current humans have been designated as subspecies Homo sapiens sapiens, differentiated from the direct ancestor, Homo sapiens idaltu.