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.
Du â¦ ring prophase I in meiosis, the two chromosomes in each homologous pair line up next to each other. This pairing process is called synapsis, and the resulting homologous pair is called a bivalent in reference to the two chromosomes or a tetrad in reference to the four sister chromatids involved.