A periodic climate pattern that occurs across the tropical Pacific Ocean every five years.
Groundwater and aquifers are types of underground waters.
Regular dice can be used for solving statistical and probability exercises.
To calculate the volume of a tetrahedron we start by calculating the volume of a prism.
Division of space by three intersecting planes in several different arrangements.
A string quartet consists of four string players, it appeared in the late 18th century.
The bell is a percussion instrument and an idiophone. Many types of bells exist.
Ports must provide necessary infrastructure and services for industry and marine transportation.
Surface epithelia cover the external and internal surfaces of the body
The reproductive system consists of organs which work together for the purpose of reproduction.
This animation demonstrates the anatomy of birds through the example of mallards.
Synovial joints can be categorised by the direction of movement they allow.
The reflex triggered by the stretching of the thigh extensor muscle is the patellar reflex.
Glands of the endocrine system secrete hormones into the blood.
The zygote is the initial cell formed when two gamete cells are joined by means of sexual reproduction.
Freshwater fish used as food in many parts of the world.
A type of snake with a characteristic spot on its neck.
The cockchafer (or maybug) is a widespread bug in Europe. Its larvae, known as chafer grubs are considered a pest.
Moles are small subterranean mammals with modified, spade-like forelegs.
A species of mollusk widespread in freshwaters.