Question

A class wanted to test the effect of increasing CO2 concentration on the amount of oxygen produced by photosynthesis. They placed elodea plants in 4 test tubes containing water at 25°C. They filled each tube with fresh water. Test tube 1 received 0.6g of baking soda to supply CO2. Test tube 2 received 0.4g of baking soda. Test tube 3 received 0.2g of baking soda. Test tube 4 received 0.0g of baking soda. A collection tube was placed over each test tube to collect the oxygen gas.

a. What is the independent variable?
A. The temperature of the water
B. The type of test tube
C. The amount of baking soda
D. The collection tube

b. What is the dependent variable?
A. The temperature of the water
B. The type of test tube
C. The amount of baking soda
D. The amount of oxygen produced

Answer 1

In the given experiment, the independent variable is the amount of baking soda added to each test tube, while the dependent variable is the amount of oxygen produced during photosynthesis, measured in the collection tubes.

Step-by-step explanation:

The student's question involves an experiment designed to test the effect of increasing CO2 concentration on the amount of oxygen produced by photosynthesis.

Independent Variable

The independent variable is what the scientists change intentionally to observe an effect on the dependent variable. In this experiment, the independent variable is C The amount of baking soda, as it is the source of CO2 and is varied across the test tubes.

Dependent Variable

The dependent variable is the outcome being measured, which changes in response to the independent variable. For this experiment, the dependent variable is D The amount of oxygen produced, as it is the variable being collected and measured in the collection tubes.