9
45%
20-30%
Air
Organisms live and grow best in
soils with almost equal amounts of
air and water, which they need to
survive. Air moves through the soil
in cracks, burrows, and pores.
Minerals
A mineral is a solid that is found
naturally and made of crystals. In soil,
the gritty mineral ingredient includes
particles called sand, silt, and clay.
Some plants grow well in sandy soils,
but others prefer soils with lots of
clay particles.
Beetles begin their lives
underground, where they
need air to breathe.
Centipedes take
in air through
holes along
their bodies.
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Turnips grow well
in loose, sandy soils.
Soil minerals are
worn away from
rocks on the surface
and from bedrock.
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008-009_The_stuff_of_soil.indd 9 08/11/2019 09: