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A rose is either a woody perennial flowering plant of the genus Rosa (/ˈroʊzə/), in the family Rosaceae (/roʊˈzeɪsiːˌiː/), or the flower it bears. There...

A virtual private network (VPN) is a mechanism for creating a secure connection between a computing device and a computer network, or between two networks...

Zoophilia is a paraphilia in which a person experiences a sexual fixation on non-human animals. Bestiality instead refers to cross-species sexual activity...

Deforestation or forest clearance is the removal and destruction of a forest or stand of trees from land that is then converted to non-forest use. Deforestation...

Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton...

A pet, or companion animal, is an animal kept primarily for a person's company or entertainment rather than as a working animal, livestock, or a laboratory...

The Pliocene ( /ˈplaɪ.əsiːn, ˈplaɪ.oʊ-/ PLY-ə-seen, PLY-oh-; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to...

AC power plugs and sockets connect devices to mains electricity to supply them with electrical power. A plug is the connector attached to an electrically-operated...

Phase Alternating Line (PAL) is a colour encoding system for analog television. It was one of three major analogue colour television standards, the others...

Spin is an intrinsic form of angular momentum carried by elementary particles, and thus by composite particles such as hadrons, atomic nuclei, and atoms...

Star clusters are large groups of stars held together by self-gravitation. Two main types of star clusters can be distinguished: globular clusters are...

In quantum physics, a wave function (or wavefunction) is a mathematical description of the quantum state of an isolated quantum system. The most common...

A toxin is a naturally occurring organic[dubious – discuss] poison produced by metabolic activities of living cells or organisms. They occur especially...

An attack aircraft, strike aircraft, or attack bomber is a tactical military aircraft that has a primary role of carrying out airstrikes with greater precision...

Human–computer interaction (HCI) is research in the design and the use of computer technology, which focuses on the interfaces between people (users) and...

Significant figures, also referred to as significant digits or sig figs, are specific digits within a number written in positional notation that carry...

A heat pump is a device that uses work to transfer heat from a cool space to a warm space by transferring thermal energy using a refrigeration cycle, cooling...

Paper size standards govern the size of sheets of paper used as writing paper, stationery, cards, and for some printed documents. The ISO 216 standard...

The expansion of the universe is the increase in distance between gravitationally unbound parts of the observable universe with time. It is an intrinsic...

A screw is an externally helical threaded fastener capable of being tightened or released by a twisting force (torque) to the head. The most common uses...