Scientists used radioactive hydrogen to make water. The scientists grew plants using the radioactive water. Based on their observations, they concluded that hydrogen is recycled during photosynthesis. Which observation provides evidence for this conclusion? (1 point)

Question

Responses

Glucose in the plant’s stem was radioactive.
Glucose in the plant’s stem was radioactive.

Water vapor near the plant was radioactive.
Water vapor near the plant was radioactive.

Light in the plant’s leaves was radioactive.
Light in the plant’s leaves was radioactive.

Hydrogen gas in the surrounding air was radioactive.

Answer 1

The observation that provides evidence for the conclusion that hydrogen is recycled during photosynthesis is:

Glucose in the plant’s stem was radioactive.

This indicates that the radioactive hydrogen from the water was incorporated into the glucose produced during photosynthesis, supporting the idea that hydrogen is recycled in the process.