Question

A scientist fills a glass container with water and places an aquatic plant inside the container, then closes the lid and places the container in direct sunlight. The scientist observes small bubbles on the surfaces of the plant's leaves on days 1 and 2, but no bubbles on day 3. The scientist concludes that the bubbles were caused by photosynthesis. Which substance should be added to the water in order for the bubbles to reappear. (1 point)
Responses

oxygen
oxygen

carbon dioxide
carbon dioxide

hydrogen gas
hydrogen gas

glucose

Answer 1

carbon dioxide

Explanation: Photosynthesis requires CO2, light, and water to produce O2. In a sealed container the dissolved CO2 can become depleted, stopping O2 production. Adding CO2 restores the substrate for photosynthesis so O2 bubbles will reappear.