Chemical element is the most stable element that can easily be made from alpha particles (being a product of decay of radioactive nickel-56, ultimately made from 14 helium nuclei). Elements heavier than iron are made in energy-absorbing processes in large stars, and their abundance in the universe (and on Earth) generally decreases with their atomic number. The abundance of the chemical elements on Earth varies from air to crust to ocean, and in various types of life. The abundance of elements in Earth's crust differs from that in the Solar system (as seen in the Sun and heavy planets like Jupiter) mainly
Lowest bridging point Lowest bridging point The lowest bridging point is the location on a river which is crossed by a bridge at its closest point to the sea. Historically - that is, before the development of engineering technology that allowed the construction of tunnels and high-level road bridges - the lowest bridging point of a river was frequently the point at which an important town or city grew up, and particularly where trade and commerce took place. The place could be served by roads on either side of the river, allowing access from a wide hinterland; had river transport available upstream; and