RESPIRATORY SYSTEM AND ENDOCRINE SYSTEM

Earth-The earth is an oblate spheroid and not a true sphere,because it is flattened at the poles and bulges out at the equator.Its circumference is 25,000 miles.
Earth in Motion-The axis of the earth is the imaginary line on which the earth rotates.
Poles-They are the end of the axis.One end is called North Pole and other the South Pole.
The Solar System-It is the name given to the group of nine major planets(Mercury,Venus,Earth,Mars,Jupiter,Saturn,Uranus,Neptune,Pluto),and their satellites,asteroids