Abundance of the chemical elements of the volatile elements hydrogen, helium, neon, and nitrogen, as well as carbon which has been lost as volatile hydrocarbons. The remaining elemental composition is roughly typical of the "rocky" inner planets, which formed in the thermal zone where solar heat drove volatile compounds into space. The Earth retains oxygen as the second-largest component of its mass (and largest atomic-fraction), mainly from this element being retained in silicate minerals which have a very high melting point and low vapor pressure. The mass-abundance of the nine most abundant elements in the Earth's crust is approximately: oxygen 46%, silicon 28%, aluminum 8.2%,
The Lowest Animal The Lowest Animal The Lowest Animal is an 1896 philosophical essay written by American author Mark Twain. Twain describes fictional experiments he did with animals in which they showed greater civility than humans. In the essay Twain satirizes human nature by describing a series of experiments he supposedly conducted at the London Zoological Gardens. Twain takes Darwin's evolution theory that humans evolved from earlier ancestors, or “lower animals,” and turns it upside down. He describes deeds done by powerful people against the helpless, and states the many ideas that made him ponder about the lack of humanity. He ends the