Select the two most important sources of energy for earth's natural systems.

plants
heat from earth's interior
wind
fossil fuels
sunlight

Sunlight and heat from earth's interior

Explanation:

Sunlight: The energy from the sun is the original source of most of the energy found on earth.We get solar heat energy from the sun, and sunlight can also be used to produce electricity from solar cells.The sun heats the earth's surface and the Earth heats the air above it, causing wind. Water evaporation by the sun forms clouds and rain to give us flowing streams and rivers. Both wind and flowing water (hydropower) are sources of energy. In conclusion, the sun is the source of many kinds of energy found on Earth.

HEAT FROM EARTH'S INTERIOR:The process by which Earth makes its own heat is called radioactive decay. It involves the disintegration of natural radioactive elements inside Earth such as uranium. Uranium is a special kind of element because when it decays, heat is produced. It’s this heat that keeps Earth from cooling off completely.

Many of the rocks in Earth’s crust and interior undergo this process of radioactive decay . This process produces subatomic particles that zip away, and later collide with surrounding material inside the Earth. Their energy of motion is converted to heat.

Without this process of radioactive decay, there would be fewer volcanoes and earthquakes – and less building of Earth’s vast mountain ranges.

there are 52 characters.

explanation:

i counted all of the letters.