The correct answer is option 2 - "Decreasing humidity: Increases, Decreasing light intensity: Decreases."

Transpiration is the process by which plants lose water to the environment through evaporation from their leaves. It is influenced by various factors.

1. Humidity: Transpiration rate increases with decreasing humidity. When the air is dry (low humidity), there is a greater difference in water vapor concentration between the inside of the leaf and the outside air. This creates a steeper gradient, which leads to more rapid water movement from the leaf to the air.

2. Light intensity: Transpiration rate decreases with decreasing light intensity. Light is necessary for photosynthesis, which produces the energy needed for plants to open their stomata. Stomata are tiny openings on the surface of leaves that allow for gas exchange, including the release of water vapor. When light intensity is low, the stomata close to prevent excessive water loss. Therefore, transpiration is reduced.

In summary, decreasing humidity leads to an increase in transpiration rate, while decreasing light intensity decreases transpiration rate.