7.4 PA STEELS Assessment: Matter Cycling & Photosynthesis

What are the main inputs required for photosynthesis?

• Oxygen and glucose

• Carbon dioxide, water, and light energy

• Nitrogen, oxygen, and sunlight

• Water, nitrogen, and glucose

How does energy flow through an ecosystem?

• The sun provides energy to plants, which is transferred to consumers and decomposers.

• Energy is created by plants and stored in the soil.

• Animals produce their own energy, which they pass to plants.

• Decomposers create energy that flows back to producers.

Which statement best explains why plants are considered producers in an ecosystem?

• They break down dead organisms to release nutrients.

• They take in food molecules from the soil.

• They use sunlight to produce food molecules through photosynthesis.

• They consume other organisms for energy.

What happens to the carbon atoms in a plant when the plant dies?

• They disappear into the air.

• They are broken down by decomposers and returned to the soil and atmosphere.

• They turn into oxygen and are released into the air.

• They remain in the dead plant forever.

Matter cycles between plants, animals, and decomposers in an ecosystem. Which of the following best describes this process?

• Plants produce oxygen and glucose, animals consume them, and decomposers break down waste into nutrients.

• Animals produce oxygen and glucose, plants consume them, and decomposers break down waste into nutrients.

• Decomposers produce oxygen and glucose, plants consume them, and animals break down waste into nutrients.

• Plants and animals both produce oxygen and glucose, and decomposers consume them.

What trend do you observe in the data?

• The data shows an increase in the light and a decrease in the dark

• The data shows a decrease in the dark and and increase in the light

• The data shows no significant trend.

• The data shows an increase in the dark and a decrease in the light

The data supports the role of photosynthesis in cycling carbon in an ecosystem by showing:

• the increase in carbon dioxide levels during photosynthesis

• the decrease in carbon dioxide levels during photosynthesis

• the increase in oxygen levels during photosynthesis

• the decrease in oxygen levels during photosynthesis

A student claims that “Plants only take in carbon dioxide; they do not release it.” Based on what you learned in this unit, explain why this statement is incorrect. Use evidence from your investigations or the data table above to support your answer.

• Plants only take in carbon dioxide during photosynthesis and release oxygen.

• Plants take in carbon dioxide and release it during respiration.

• Plants only release carbon dioxide at night.

• Plants neither take in nor release carbon dioxide.

What is the main purpose of photosynthesis?

• To produce oxygen for animals to breathe

• To convert sunlight into chemical energy stored in glucose

• To remove carbon dioxide from the atmosphere permanently

• To provide water for plant growth

What is the primary function of photosynthesis?

• It provides energy to convert carbon dioxide and water into glucose

• It directly becomes glucose in the plant

• It reacts with oxygen to form carbohydrates