It is winter in the Northern hemisphere when...
The revolution of the Earth is...
The rotation of the Earth is ...
It is summer in the Northern hemisphere when...
It is spring or autumn when...
The seasons are the result of...
the tilt of the Earth and its orbit round the Sun.
the Sun´s rays fall on the Equator.
its movement around its own axis.
its elliptical orbit around the Sun.
the Sun´s rays fall on the Southern hemisphere.
the Sun´s rays fall on the Northern hemisphere.
