A stalagmite is a type of speleothem that rises from the floor of a limestone cave due to the dripping of mineralized solutions and the deposition of calcium carbonate.
The corresponding formation ... > more
Mean sea level (MSL) is the average (mean) height of the sea, with reference to a suitable reference surface. Defining the reference level, however, involves complex measurement, and accurately ... > more
The lithosphere is the solid outermost shell of a rocky planet. On the Earth, the lithosphere includes the crust and the uppermost layer of the mantle (the upper mantle or lower lithosphere) which is ... > more
Structural alignment is a form of sequence alignment based on comparison of shape. These alignments attempt to establish equivalences between two or more polymer structures based on their shape and ... > more
The evolution of the eye has been a subject of significant study, as a distinctive example of a homologous organ present in a wide variety of species. The development of the eye is considered by most ... > more
Priapulida are a phylum of marine worms with an extensible spiny proboscis. Priapulid fossils are known at least as far back as the Middle Cambrian. Their nearest relatives are probably Kinorhyncha ... > more
The Cretaceous-Tertiary extinction event was a period of massive extinction of species, about 65.5 million years ago. It corresponds to the end of the Cretaceous Period and the beginning of the ... > more
Carbon-14, 14C, or radiocarbon, is a radioactive isotope of carbon discovered on February 27, 1940, by Martin Kamen and Sam Ruben. Its nucleus contains 6 protons and 8 neutrons. Its presence in ... > more
The Brachiosaurus is a famous dinosaur that lived during the Jurassic period. One of the largest ever dinosaurs to walk the earth, it has become a famous animal synonymous with dinosaurs, and is ... > more
In geology, a crust is the outermost layer of a planet.
The crust of the Earth is composed of a great variety of igneous, metamorphic, and sedimentary rocks. The crust is underlain by the mantle. ... > more