1% of the absorbed water is used by plants in its activities during:

Explanation

The correct answer is Photosynthesis. During photosynthesis, plants use about 1% of the absorbed water to convert carbon dioxide and light into glucose and oxygen. This process is critical for plant growth and energy production. Other options, like metabolism and respiration, involve water, but they do not specifically use 1% of the absorbed water. Vernalization is unrelated to water usage as it pertains to the flowering process induced by cold exposure.