Guard cells help in transpiration. Transpiration is the evaporation of water from the aerial parts of plants, especially leaves but also stems, flowers and roots. Stomatal opening allows the diffusion of carbon dioxide and oxygen during photosynthesis.

Correct Option: A

Guard cells help in transpiration. Transpiration is the evaporation of water from the aerial parts of plants, especially leaves but also stems, flowers and roots. Stomatal opening allows the diffusion of carbon dioxide and oxygen during photosynthesis.

Transpiration creates pulling (Negative pressure) force. Root pressure creates positive pressure developed in xylem. It is measured by manometer.

Correct Option: A

Transpiration creates pulling (Negative pressure) force. Root pressure creates positive pressure developed in xylem. It is measured by manometer.

Water movement occurs through the tracheary elements of xylem.

Correct Option: C

Water movement occurs through the tracheary elements of xylem.

Transpiration pull and cohesion theory was put forward by Dixon and Jolly in 1894. According to this theory water rises due to the transpiration pull, continuity of water column and the cohesive power of water molecules from the lower part of the roots to the higher peaks of the trees.

Correct Option: D

Transpiration pull and cohesion theory was put forward by Dixon and Jolly in 1894. According to this theory water rises due to the transpiration pull, continuity of water column and the cohesive power of water molecules from the lower part of the roots to the higher peaks of the trees.