Larvae of this type of mayflies spend the first three years of their lives in water, their adult lives last for only one day which they use for mating.
A type of herbivorous dinosaur easily recognisable by its large frill and three horns which lived in the Cretaceous period.
The pericarp of real fruits develops from the carpel, while the pericarp of pseudofruits develops from other parts of flowers.
The Ottoman army included janissaries (paid warriors) and sipahis (vassal knights).
An ant colony consist of a queen, male ants and workers.
Honeybees produce a sweet and nutritious substance, honey.
Chlorophyll is a photosensitive green pigment found in plants; it absorbs light energy, thus plays a vital role in photosynthesis.
Public schools in villages played an important role in education.
System that satisfies consumers’ demands of water supply, wastewater disposal, electricity, heat and gas supply and telecommunication.
This animation demonstrates the main sources of air pollution: agriculture, industry and urban settlements.
Airports provide infrastructure and services necessary for aviation.
Ports must provide necessary infrastructure and services for industry and marine transport.
The Northern white-breasted hedgehog rolls into a ball to protect itself.
The Emperor of the vast Far-Eastern empire was the lord of life and death.
The battle ended with the overwhelming victory of the Macedonian army over the Persian army led by Darius III.
Two meshing gears transmit torque during their rotational motion.
One of the most important religious military orders, formed in the era of the Crusades.
Keeps were typical buildings in the Middle Ages, also built independently from castles.
The least tightly packed crystal structure.
The Hubble Space Telescope orbits outside the distorting influence of Earth´s atmosphere.