[ad_1] Bilateria is a subkingdom of the animal kingdom, consisting of all animals except sponges, cnidarians, and ctenophores. They share common characteristics such as three primary tissue layers, bilateral symmetry, and a coelom. The first known bilaterian, Vernanimacula, lived 600 million years ago in China. Bilaterians have a coelom, which allows for sophisticated movement and […]