Question

1. a student placed a test tube containing elodea (an aquatic plant) and pond water 10 cm from a light source. he observed that the plant gave off bubbles of a gas and counted how many bubbles were released in one minute. he moved the plant farther away from the light source to see if distance from the source made a difference. the data table below shows his results.

the gas that was being produced was most likely

image of a test tube with elodea and a light source arrow

gas production

distance from light (cm)	bubbles produced per minute
20	30
30	7
40	4

• carbon dioxide as a product of the process of respiration
• carbon dioxide as a product of the process of photosynthesis
• oxygen as a product of the process of respiration
• oxygen as a product of the process of photosynthesis

Explanation:

The experiment involves an aquatic plant (elodea) producing gas in response to light. Photosynthesis is the process by which plants use light energy to convert carbon dioxide and water into glucose and oxygen. The data shows gas production decreases with increasing distance from light, which aligns with photosynthesis (since light is a key reactant). Oxygen is a byproduct of photosynthesis, while respiration produces carbon dioxide (not dependent on light in this context).

Answer:

oxygen as a product of the process of photosynthesis