The International System of Units

The International System of Units is the modern form of the metric system. It is the world's most widely used system of units, both in everyday commerce and in science.
The older metric system included several groupings of units. The SI was developed in 1960 from the metre-kilogram-second system, rather than the centimetre-gram-second system which, in turn, had many variants.
The SI introduced several newly named units. The SI is not static; it is a living set of standards where units are created and definitions are modified with international agreement as measurement technology progresses.
With few exceptions, the system is used in every country in the world, and many countries do not maintain official definitions of other units. In the United States, industrial use of SI is increasing, but popular use is still limited. In the United Kingdom, conversion to metric units is official policy but not yet complete. Those countries that still recognize non-SI units have redefined their traditional non-SI units in terms of SI units.

Seahorses

Seahorses are marine fish belonging to the genus Hippocampus of the family Syngnathidae, which also includes pipefish. They are found in temperate and tropical waters all over the world.
Seahorses range in size from 16 mm to 35 cm. Seahorses and pipe fishes are notable for being the only species in which males become "pregnant”. The seahorse is a true fish, with a dorsal fin located on the lower body and pectoral fins located on the head near their gills. Some species of seahorse are partly transparent and are rarely seen in pictures.
Seahorse populations have been endangered in recent years by over fishing. The seahorse is used in traditional Chinese herbology, and as many as 20 million seahorses may be caught each year and sold for this purpose.
Import and export of seahorses has been controlled under CITES since May 15, 2004.Sea dragons are close relatives of seahorses but have bigger bodies and leaf-like appendages which enable them to hide among floating seaweed or kelp beds. Sea dragons feed on larval fishes and amphipods, such as small shrimp-like crustaceans called mysids, sucking up their prey with their small mouths. Many of these amphipods feed on red algae that thrives in the shade of the kelp forests where the sea dragons live.

Tank

A tank is a tracked armoured fighting vehicle, designed to engage enemy forces by the use of direct fire. A tank is characterized by heavy weapons and armour, as well as by a high degree of mobility that allows it to cross rough terrain at relatively high speeds. While tanks are expensive to operate and logistically demanding, they are among the most formidable and versatile weapons of the modern battlefield, both for their ability to engage other ground targets and their shock value against infantry.
While tanks are powerful fighting machines, they seldom operate alone, being organized into armoured units in combined arms forces. Without such support, tanks, despite their armour and mobility, are vulnerable to infantry, mines, artillery, and air power. Tanks are also at a disadvantage in wooded terrain and urban environments, which cancel the advantages of the tank's long-range firepower, limit the crew's ability to detect potential threats, and can even limit the turret's ability to traverse.
Tanks were first used in the First World War to break the deadlock of the trenches, and they evolved gradually to assume the role of cavalry on the battlefield. The name tank first arose in British factories making the hulls of the first battle tanks: the workmen were given the impression they were constructing tracked water containers for the British Army, hence keeping the production of a fighting vehicle secret.
During WW1 two major types of tanks evolved; the "male tank" which is the vehicle associated with the word today, and the female tank. The female tank contained a series of smaller weapons located around the hull as opposed to the single large weapon seen on today's tanks, and was mainly designed as an anti-infantry platform. After WW1 ended this type of vehicle was largely replaced by infantry carriers.
Tanks and armour tactics have undergone many generations of evolution over nearly a century. Although weapons systems and armour continue to be developed, many nations have reconsidered the need for such heavy weaponry in a period characterized by unconventional warfare.

Capital punishment

Capital punishment, or the death penalty, is the execution of a convicted criminal by the state as punishment for crimes known as capital crimes or capital offences. Historically, the execution of criminals and political opponents was used by nearly all societies - both to punish crime and to suppress political dissent. Among democratic countries around the world, most European and Latin American states have abolished capital punishment while the United States, Guatemala, and most of the Caribbean as well as democracies in Asia and Africa retain it. Among nondemocratic countries, the use of the death penalty is common but not universal.
In most places that practice capital punishment today, the death penalty is reserved as a punishment for premeditated murder, espionage, treason, or as part of military justice. In some countries with a Muslim majority, sexual crimes, including adultery and sodomy, carry the death penalty, as do religious crimes such as apostasy from Islam, the formal renunciation of one's religion. In many retentionist countries drug trafficking is also a capital offense. In China human trafficking and serious cases of corruption are also punished by the death penalty. In militaries around the world courts-martial have imposed death sentences for offenses such as cowardice, desertion, insubordination, and mutiny.
Capital punishment is a contentious issue. Supporters of capital punishment argue that it deters crime, prevents recidivism, and is an appropriate punishment for the crime of murder. Opponents of capital punishment argue that it does not deter criminals more than life imprisonment, violates human rights, leads to executions of some who are wrongfully convicted, and discriminates against minorities and the poor.