Chihuahua Dog Breed. First discovered in Mexico, the Chihuahua is best known for being the smallest dog breed in the world. Extremely loyal to its owner, the breed has recently become a popular culture icon in the United States, most notably Paris Hilton's Chihuahua, Tinkerbell. Physical Characteristics.
Earth formed around 4.54 billion years ago by accretion from the solar nebula. Volcanic outgassing probably created the primordial atmosphere and then the ocean; but the atmosphere contained almost no oxygen and so would have been toxic to most modern life including humans.
How Did Life First Appear. The fact that life began on earth is just a natural consequence of the known fundamental laws of chemistry and physics. Life was inevitable, once certain conditions prevailed.ow Did Life First Appear. The fact that life began on earth is just a natural consequence of the known fundamental laws of chemistry and physics. Life was inevitable, once certain conditions prevailed.