Science

Food chains

Ecosystems

Living things

cells

Airflow

Gravity

Geology

Energy

Velocity

Rocks and minerals

Energy hunters

Core, mantle and crust

Hearing and differation of the earth

Study of the earth

Gears

The number of teeth are the elements of gears

Plastic

Steel

Transmit rotary motion from one shaft to another

Gears are mechanisms that mesh together

Chemical reacions

Oxygen

H2O

Oxegyn

Dihydrogen oxide

Solids, liquids, gases and orgasims in various earth systems

Hydrogen

Solar system

5 dwarf planets

Pluto

Eris

Ceres

Makemake

Meteorites

Space rocks

Asteroids

Comets

Meteors

Meteorites

Planets

8 planets in the solar system

Galaxies

Galaxies are between 10 billion and 13.6 billion years old