Question

Scientists inferred that the fish raised in elevated carbon dioxide levels suffered from a loss of hearing. What evidence suggests this? (A) High levels of dissolved carbon dioxide can increase the acidity of water and potentially harm the marine life living there. (B) The positions of the fish in each tank were recorded throughout the experiment. (C) One hundred fertilized eggs from the same parent fish were placed in three separate tanks of water. (D) It was found that the fish raised in elevated carbon dioxide levels did not avoid the sound of the predators.

Short answer

(D) It was found that the fish raised in elevated carbon dioxide levels did not avoid the sound of the predators.

Step-by-step solution

Option A

High levels of dissolved carbon dioxide can increase the acidity of water and potentially harm the marine life living there. Option A explains the general potential harm that elevated levels of carbon dioxide can cause to marine life. However, it doesn't directly provide any evidence for the loss of hearing in these fish.

Option B

The positions of the fish in each tank were recorded throughout the experiment. Option B mentions the design element of the experiment. It states that the positions of the fish were recorded but doesn't yet provide any evidence indicating the loss of hearing in fish raised in elevated carbon dioxide levels.

Option C

One hundred fertilized eggs from the same parent fish were placed in three separate tanks of water. Option C provides some information about the initial setup of the experiment, describing how the fish were separated into different tanks. However, it doesn't show any evidence related to the hearing loss in fish raised in elevated carbon dioxide levels.

Option D

It was found that the fish raised in elevated carbon dioxide levels did not avoid the sound of the predators. Option D provides clear evidence that indicates a loss of hearing in fish raised in elevated carbon dioxide levels. While fish is expected to avoid the sound of predators, here it is mentioned that fish did not avoid the predators' sound, which may indicate that they were not able to hear it properly. Based on the analysis of each option, we can conclude that the correct answer is:

Answer

(D) It was found that the fish raised in elevated carbon dioxide levels did not avoid the sound of the predators.

Key concepts

Carbon Dioxide Levels

Carbon dioxide (CO2) is a common gas found in Earth's atmosphere. Its levels fluctuate naturally, but human activities like burning fossil fuels have increased its concentration significantly in recent years. The rise in carbon dioxide levels can affect many ecosystems, especially aquatic environments where gases can dissolve in water.
When CO2 dissolves in water, it forms carbonic acid, which can lead to increases in water acidity. Scientists often study carbon dioxide levels to understand their impact on various ecological systems, as their elevated presence can disrupt natural processes.

• Human activities contribute significantly to CO2 emissions.
• Rising CO2 levels affect air and water acidity.
• Scientific studies often explore the consequences of these changes on ecosystems.

Marine Life

Marine life encompasses all living organisms in oceans and seas, including fish, corals, and plants like sea grass. These organisms depend on specific conditions to survive, such as temperature, salinity, and appropriate pH levels.
Changes in carbon dioxide levels affect marine life in several ways. For example, increased CO2 can threaten the health of marine species by altering their habitat conditions. Fish, corals, and shellfish are particularly sensitive to changes in water chemistry, which can lead to behavioral and physiological changes.

• Marine life includes a diverse range of organisms dependent on stable environments.
• Alterations in water conditions can impact marine organisms' health and behavior.
• Species may face threats from changes in water chemistry due to increased CO2 levels.

Experimental Design

Experimental design is a structured method for conducting scientific research, intended to test hypotheses and draw conclusions. It's vital for ensuring that experiments are valid, reliable, and reproducible.
In the exercise mentioned, the experiment involved placing one hundred fertilized fish eggs in different tanks with varying carbon dioxide levels. By monitoring these conditions, researchers aimed to observe behavioral changes related to hearing in fish. Proper experimental design involves variables, controls, randomization, and replication to ensure accurate findings.

• Clear and structured design enhances the validity of scientific research.
• Using controls and varying conditions helps pinpoint cause-and-effect relationships.
• Replication and randomization add reliability to experimental results.

Acidity of Water

The acidity of water, measured by the pH scale, determines the concentration of hydrogen ions in a solution. A lower pH indicates higher acidity, which can drastically affect aquatic life.
When carbon dioxide dissolves in water, it forms carbonic acid, leading to a decrease in pH. This increase in acidity can harm organisms that are not adapted to such conditions. For marine species, changes in water acidity affect shell formation, reproduction, and other physiological processes.

• The pH scale measures the acidity or basicity of a solution.
• Carbon dioxide dissolution creates carbonic acid, decreasing water pH.
• Altered acidity impacts marine organisms' ability to grow and reproduce.