A scientist feels like glass container with water and places in aquatic plant inside the container, then closes the lid and places the container and direct sunlight. The scientist observes small bubbles on the surface of the plants leaves on days one and two, but no bubbles on day 3. The scientists 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)

A carbon dioxide
B oxygen
C hydrogen gas
D glucose

1 answer

The correct answer is A carbon dioxide.

Photosynthesis requires carbon dioxide (CO₂) in order to produce glucose and oxygen (O₂) using sunlight. The bubbles observed on the plant's leaves are likely oxygen produced as a byproduct of the photosynthesis process. If there is not enough carbon dioxide in the water, the plant may not be able to perform photosynthesis efficiently, leading to fewer or no bubbles. Adding carbon dioxide to the water would increase the photosynthesis process and likely cause the bubbles to reappear.