The range of applications of unmanned aerial vehicles ('drones') keeps growing.
Practise the German alphabet and form words from the letters.
Colourless, odourless liquid produced by dissolving carbon dioxide in water.
By positron emission tomography (PET), we can obtain visual information on our internal organs without making any surgical incisions.
This scene explains the structure and functions of the bones.
The adrenal glands are responsible for maintaining homeostasis and producing a rapid response in stressful situations.
There are two basic cell types: prokaryotic and eukaryotic cells.
Practise the Russian alphabet, build words from letters.
Practise the English alphabet, build words from letters.
Structures consisting of enormous stone blocks, dating back thousands of years, are monuments of megalithic cultures.
Waterfalls form where a river flows over a steep precipice in its course.
The ancestors of Arachnida and Crustacea belonged to the class Trilobita.
A type of sugar found in mammalian milk.
Entertaining and spectacular animation to practise orientation in space.
The German engineer Otto Lilienthal was the first person to make successful flights with a glider designed by himself.
Articulated lorries play an important role in road transport.
Several analogous types of eyes have developed independently through convergent evolution.
The American Civil War was fought between the Confederacy and the Union.
Edison´s invention records and plays sound from a cylinder, while Berliner´s apparatus uses a disc.
The medieval bell tower of the Cathedral of Pisa is the most famous leaning tower of the world.