The phosphorus cycle describes the movement of phosphorus through the lithosphere, hydrosphere, and biosphere.
Freshwater fish used as food in many parts of the world.
Viking leaders were elected from tribe members by the right of blood or an act of bravery.
This animation demonstrates the anatomy of amphibians through the example of a common species of frogs.
Moles are small subterranean mammals with modified, spade-like forelegs.
A species of mollusc widespread in freshwaters.
The anatomy of annelids is demonstrated through the example of the common earthworm.
One of the most important monocot crops.
Jellyfish are free-swimming marine animals, a species of Cnidaria, the most ancient group of Eumetazoans.
The most ancient group of animals, they live underwater, lack real tissues and body symmetry.
Widespread heterotrophic unicellular organisms with constantly changing shapes
Triglycerides containing unsaturated fatty acids are liquid at room temperature.
Three saturated fatty acid molecules linked to a glycerol molecule.
Common ciliated eucaryotic unicellular organisms widespread in freshwaters.
This animation demonstrates the anatomy of birds through the example of mallards.
A string quartet consists of four string players, it appeared in the late 18th century.
The reflex triggered by the stretching of the thigh extensor muscle is the patellar reflex.
Observatories are often built at high elevations to minimise the effects of atmospheric turbulence
The piano is one of the most popular instruments in the world. It is a chordophone which produces sounds mechanically.
The battle ended with the overwhelming victory of the Macedonian army over the Persian army led by Darius III.