Carbon Cycle Homework Answer Key

Carbon Cycle Questions
1. Macronutrients are nutrients that
are used by organisms in large
quantities. Macronutrients include
Carbon, Hydrogen, Oxygen, Nitrogen,
and Phosphorus. Micronutrients are
nutrients that are used in small amounts
by living things. Micronutrients include
Iron, Iodine, and Zinc. Both macro and
micro nutrients are recycled on Earth.
They are passed back and forth between
living and non-living components of the
ecosystem in processes called
biogeochemical cycles.
2. Primary producers take carbon
dioxide from the atmosphere, release
oxygen back into the atmosphere, and
fix organic compounds (glucose, starch,
Secondary consumers eat producers,
respirate, releasing energy in the body
and carbon dioxide into the atmosphere.
Decomposers break down dead
producers, consumers, and waste. As
they break these down they respirate
returning carbon dioxide to the
atmosphere and nutrients to the soil.
3. Most of Earth’s carbon is located in
the atmosphere as a gas.
4. Carbon enters the biotic (living) part
of an ecosystem through plants in
5. Plants in a forest take in carbon
dioxide and use it to form glucose,
starch, and cellulose.
6. Carbon dioxide is returned to the
atmosphere through respiration of
plants, animals, and decomposers.
7. A primary producer is a plant that
can produce its own food.
8. When a primary and secondary
consumer die they decay. Decomposers
break down their remains, returning
nutrients to the soil, and releasing
carbon dioxide through respiration.
9. Detritus feeders feed on dead bodies
and waste. They respirate and return
carbon dioxide to the air.
10. A fossil fuel is organic matter that
has been buried deep in Earth and
undergoes high pressure and
temperatures for a very long time.
Organic matter is anything that was
once living. This means the organic
matter contains carbon since it was once
11. Carbon in the air dissolves into
oceans, and combines with calcium to
form calcium carbonate. Calcium
carbonate is incorporated into the shells
of mollusks and other creatures. When
these organisms die and decay, the
shells transform into limestone, which,
over time, dissolves as it sits in water.
Carbon is released from the limestone
and may return to the atmosphere
through volcanic eruption (if trapped in
rock) or diffusion (if in water).
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