The refers to the sum total of all life on earth.

What causes the cycle of seasons on earth? the tilt of earth’s axis the shape of earth’s orbit the direction of earth’s orbit the distance between earth and the sun

In the late 1990s, brazil’s poor people protested about crowded cities land distribution mining permits industrial pollution

1. crust 1 the metallic layer at the earth's center 2. inner core 3 the firm layer between the crust and the asthenosphere 3. lower mantle 2 the layer surrounding the inner core 4. asthenosphere 4 the semi-solid layer between the top layer and the upper mantle 5. upper mantle 5 the layer between the asthenosphere and lower mantle 6. top layer 6 the earth's outermost layer 7. outer core 7 the hottest part of the mantle