A geyser is a spring characterised by intermittent discharge of water and steam.
The migration of large human populations began in Ancient times.
A fjord is a long, narrow inlet with steep sides, created in a valley carved by glacial activity.
The most important weapons of medieval Arab warriors were the bow and the sword.
Every era and every culture has specific residential buildings.
Its architectural solutions and ornamentation rank this mosque among the masterpieces of Islamic art.
One of the positive influences of the Ottoman invasion of Europe was the construction of baths.
The diameter of our galaxy is about 100,000 light years; it contains more than 100 billion stars, one of which is our Sun.
The water supply system provides clean and safe drinking water for the consumers.
ATP is the main source of energy for cells.
During swallowing food travels from the mouth cavity into the stomach.
The knee joint is made up by the femur, the tibia and the kneecap.
A game to practise the use of analogue and digital clocks.
NAD⁺ is a coenzyme that plays an important role mainly in catabolic processes, while NADP is important in anabolic processes as hydrogen carriers.
Igloos were the typical dwellings built by Eskimos living in the Arctic zone.
The Aztec Empire was a despotic, militaristic state ruled by the tlatoani.
The ruler of the vast Mongol Empire was the Khan.
The reproductive system is a series of organs working together for the purpose of reproduction.
The three main types of blood vessels in the human body are the arteries, the veins, and the capillaries.
Common ciliated eucaryotic unicellular organisms widespread in freshwaters.