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