Which of the following traits of land plants allows them to grow in height?

a. alternation of generations

b. waxy cuticle

c. tracheid

d. sporopollenin

Definition of tracheid :

• It is a part of the xylem which has a single elongated cell.
• It forms an essential part of all vascular plants.
• The function of tracheid is to conduct water and mineral circulation to all parts of plants.

Explanation of how tracheid help plants to achieve height:

• The other function of tracheid is to provide mechanical support to plants.
• It serves that function with the help of lignin.
• The presence of lignin in the cell walls of the plants makes the wall thick and stiff.
• Hence, the tracheid helps in the upward conduction of water along with giving pants support to achieve height.

• Alternation of generation is a process of sexual and asexual reproduction in plants and does not have any role in the growth and support of plant.
• Waxy cuticle functions to prevent excessive water loss in plants.
• Sporopollenin functions to prevent the pollen seeds from harsh weather conditions.

Hence, we can say that none of the options serves as the solution to the question.