Science Test: Unit 7

weathering is the process in which rocks are _____________ and ______________

broken down, changed

when the composition of rocks are changed, this is called ______________

chemical weathering

burning fossil fuels causes minerals to wear away in this type of chemical weathering

acid precipitation

when_____________________ dissolves in water, marble and limestone are weathered

carbon dioxide

soil is an _________________ for many animals


many of the __________________ that humans rely on come from soil


the type of soils that hold water would have _____________ present


_______________ is rich, fertile soil that is made up of about equal parts of clay, sand, and silt


soil development takes a long time. even in the best conditions, soil scientists estimate that soil will form around __________________________________

one millimeter per year

_____________________ is the most important factor because it can produce a particular type of soil, regardless of the parent rock. increased precipitation and temperature speed up ____________________ reactions, which then speeds up weathering.

climate, chemical

the original rock is called the _______________ rock. soil may form in place, which is referred to as _______________ soil, or it may come from somewhere else.

parent, residual

_____________ and _________________ produce the organic material in soil. a very important part of the soil is called ____________________ forms from the remains of them. it is important because it is responsible for holding the soil together, which allow

plants, animals, humus

________________________consists of the o and a layers. the o, or organic, layer is the darker layer of soil, and it is the layer with the most humus or organic material. the a layer is where most biological activity takes place and roots grow here to kee


subsoil consists of the ___ and ___ layers. an accumulation of clay can be found here, and there is less biological activity here. There can be signs of weathering, and the_______________rock can even be identified here.

b, c, parent

the ____ horizon is the underlying geological material, or bedrock, in which soil horizons form.