According to the table below, how does carbon dioxide affect the rate of photosynthesis?
| | Full $CO _2$ | Half $CO _2$ |
| :-------------------- | :----------- | :----------- |
| Number of bubbles (30 sec) | 30 | 16 |
A. It increases the rate of photosynthesis.
B. It decreases the rate of photosynthesis.
C. The rate of photosynthesis stays the same.
D. It triples the rate of photosynthesis.
Answer (2)
Calculate the rate of bubble production with full C O 2 : 30 30 = 1 bubble/second.
Calculate the rate of bubble production with half C O 2 : 30 16 = 15 8 bubble/second.
Compare the rates: \frac{8}{15}"> 1 > 15 8 , indicating a higher rate with full C O 2 .
Conclude that carbon dioxide increases the rate of photosynthesis: It increases the rate of photosynthesis.
Explanation
Understanding the Problem The table shows the number of bubbles produced in 30 seconds under two different carbon dioxide conditions: full C O 2 and half C O 2 . We need to determine how carbon dioxide affects the rate of photosynthesis based on this data.
Calculating the Rates First, let's calculate the rate of bubble production (bubbles per second) for both full C O 2 and half C O 2 conditions. This will allow us to compare the rates and see how carbon dioxide concentration affects the rate of photosynthesis.
Calculating Bubble Production Rates For the full C O 2 condition, we have 30 bubbles produced in 30 seconds. Therefore, the rate is: Rate full = 30 seconds 30 bubbles = 1 bubble/second For the half C O 2 condition, we have 16 bubbles produced in 30 seconds. Therefore, the rate is: Rate half = 30 seconds 16 bubbles = 15 8 bubble/second ≈ 0.53 bubble/second
Comparing the Rates Now, let's compare the two rates. We have: Rate full = 1 bubble/second Rate half ≈ 0.53 bubble/second Since 0.53"> 1 > 0.53 , the rate of bubble production is higher with full C O 2 than with half C O 2 . This indicates that a higher concentration of carbon dioxide increases the rate of photosynthesis.
Conclusion Based on our calculations, increasing the carbon dioxide concentration increases the rate of photosynthesis. Therefore, the correct answer is: It increases the rate of photosynthesis.
Examples
Understanding how carbon dioxide affects photosynthesis is crucial in agriculture. Farmers can optimize the environment in greenhouses by controlling C O 2 levels to enhance plant growth and crop yield. For example, if a farmer knows that increasing C O 2 from half to full concentration nearly doubles the rate of photosynthesis (as seen in the table), they can invest in systems that maintain optimal C O 2 levels, leading to healthier plants and more abundant harvests. This principle is also vital in understanding broader ecological impacts, such as how rising atmospheric C O 2 levels influence global plant productivity.
The data shows that increasing carbon dioxide levels leads to a higher rate of photosynthesis, indicated by more bubbles produced in the full C O 2 condition compared to half C O 2 . Therefore, the answer is A. It increases the rate of photosynthesis.
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