Testwizard for 11/17 Quiz

The element carbon and its compounds are constantly cycled between the living and nonliving parts of the ecosystem. This cycling is important because

• 
  Without carbon dioxide in the atmosphere, the ozone shield would break down completely

• 
  Carbon is a component of DNA, proteins, and other compounds essential for living organisms

• 
  The process of photosynthesis releases carbon dioxide into the atmosphere, where it can be taken in by animals for the process of respiration

• 
  Carbon is required by humans to make all of the same proteins that all other mammals synthesize

The information and graph below and on your knowledge of biology. The graph below shows changes in dissolved oxygen in a pond in the summertime over a 24-hour period.

A large population of fish was introduced into the pond. During which part of the day would these fish affect the dissolved oxygen level in the pond?

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  Both day and night, because respiration is occurring all the time in plants and animals

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  Nighttime, because no respiration is occurring

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  Daytime, because that is when plants are most active

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  Neither day nor night, because only plants produce oxygen

The information and graph below and on your knowledge of biology. The graph below shows changes in dissolved oxygen in a pond in the summertime over a 24-hour period.

What is the most likely reason for the variation in the dissolved oxygen levels in the pond over the 24-hour period?

• The increased light during the day decreases the oxygen produced by photosynthesis.

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  Photosynthesis produces more oxygen during the day than is used by respiration.

• 
  
  Respiration is reduced at night, so the oxygen produced by photosynthesis increases.

• 
  More producers are active at night, so the dissolved oxygen increases.

Carbon dioxide and oxygen are important resources in ecosystems and are

• Recycled through the activity of living and nonliving systems

• Stored in the animals of the ecosystem

• Lost due to the activities of decomposers

• 
  Released by the process of photosynthesis

The diagram below represents a cycle that occurs in nature.

Which phrase describes a human activity that could have a negative effect on this cycle?

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  A decrease in the amount of sulfates given off by motor vehicles

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  An increase in recycling programs for plastics and metals

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  The continued deforestation and removal of forest resources

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  Development of programs to conserve wildlife

Which two processes are responsible for keeping the percentage of atmospheric oxygen at relatively constant levels?

• 
  Circulation and coordination

• 
  Respiration and coordination

• Respiration and photosynthesis

• 
  Photosynthesis and circulation

The diagram below represents a cycling of materials.

Which row in the chart below shows the substances represented by X and Y?

• 1

• 2

• 3

• 4

Millions of acres of tropical rain forest are being destroyed each year. Which change would most likely occur over time if the burning and clearing of these forests were stopped?

• An increase in the amount of atmospheric pollution produced

• A decrease in the source of new medicines

• 
  An increase in the amount of oxygen released into the atmosphere

• A decrease in the number of species

A five-year study was carried out on a population of algae in a lake. The study found that the algae population was steadily decreasing in size. Over the five-year period this decrease most likely led to

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  A decrease in the amount of nitrogen released into the atmosphere

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  An increase in the amount of oxygen present in the lake

• An increase in the amount of water vapor present in the atmosphere

• A decrease in the amount of oxygen released into the lake

In an ecosystem, which component is not recycled?

• Water

• Energy

• Oxygen

• Carbon