The reflex triggered by the stretching of the thigh extensor muscle is the patellar reflex.
The zygote is the initial cell formed when two gamete cells are joined by means of sexual reproduction.
Glands of the endocrine system secrete hormones into the blood.
A mammal with features typical of reptiles: it lays eggs and has a cloaca.
The reproductive system is a series of organs working together for the purpose of reproduction.
Careful tooth brushing is an important part of oral hygiene.
To calculate the volume of a tetrahedron we start by calculating the volume of a prism.
An extinct group of Cephalopoda, with solid external skeletons. They are excellent index fossils.
The knee joint is made up by the femur, the tibia and the kneecap.
A long pipe in the centre of the tower penetrates the ocean bed until it reaches the layer that contains oil.
Ports must provide necessary infrastructure and services for industry and marine transport.
The European badger is an omnivorous, nocturnal animal. Badger colonies live in large burrow systems, called setts.
While the density of spider silk is less than that of nylon filaments, its tensile strength is greater than that of steel.
The name of the Russian armoured cruiser became well known during the October Revolution of 1917.
Long-necked herbivorous dinosaur with a robust body.
Trolleybuses and trams are environment-friendly means of public transport
A group of fish characterised by a cartilaginous skeleton, well-known species include the great white shark and the great hammerhead shark.
This animation demonstrates how an escalator works.
This animation presents the states and state capitals of Germany
Machines powered by animals were mainly used in mills, for grinding grains.