Gold(Au) - Gold is a highly sought-after rare metallic element. For many centuries gold has been used for money, jewellery and ornamentation symbolising wealth and prosperity. Like other precious metals, gold is measured by troy weight and by grams. When it is alloyed with other metals the term carat (or karat in the USA) is used to indicate the amount of gold present. Pure gold is twenty-four twenty-fourths (24/24ths) gold, and is called 24-carat gold.
Reptiles are a group (Reptilia) of tetrapod animals comprising today's turtles, crocodilians, snakes, lizards, tuatara, and their extinct relatives.
Synapsids ('fused arch'), also known as theropsids ('beast face'), are a class of animals that includes mammals and everything closer to mammals than to other living amniotes.The non-mammalian members were traditionally described as mammal-like reptiles, and are sometimes referred to as proto-mammals or stem-mammals.