All organisms on Earth ride upon a "ferrous wheel" made of different forms of iron that are essential for life. Aa Aa Aa Biogeochemical cycles describe pathways by which chemical elements move through ...

Iron makes up about 5 per cent of the Earth's crust and is the most abundant element in the whole Earth (about 35 per cent). It is the second most abundant metal after aluminium and the fourth most ...

There are lots of different substances but only just over a hundred elements. An element is a substance that is made up of only one kind of atom. The atoms in a particular element are the same as each ...

Four and a half billion years ago, after Earth’s fiery birth, the infant planet began to radically reshape itself, separating into distinct layers. Metals — mostly iron with a bit of nickel — fell ...