For those wanting to know what the new Snapchat emoji symbols mean, there is several different things that they repersent and these emojis have replaced the âBest Friendsâ feature with Friend Emojis smilies.
(plural tetrads) 1  A group of four things. ( 2 chemistry) A tetravalent atom or radical. ( biology) Two pairs of sister chromatids (a dyad pair) aligned in a certain way and often on the equatorial plane during the meiosis process.
One of the most useful features in classifying tetrapods is the skull, a collection of bones which surrounds the brain, and includes the jaw. The structure and arrangement of the bones in the skull is what gives the major groups of amniote tetrapods their names.The Anapsida, Diapsida, and Synapsida are defined by the number of openings on each side of the skull: zero, two, and one, respectively.etrapods have four limbs. Tetrapod means four feet, and all tetrapods -- except for highly modified forms, such as snakes -- have four limbs with the same basic structure.