Extra

• What substance do tracheid cell walls contain?

  Lignin
• What are the properties of lignin in tracheid cell walls?

  Hard, strong, and waterproof
• What are the gaps in tracheid cell walls called?

  Pits
• How does water travel through tracheids?

  Through pits in a twisting path
• Why is the path of water through tracheids less efficient?

  It takes a twisting path rather than straight
• What type of plant has become dominant on Earth due to efficient water movement?

  Angiosperms
• What is the difference in water movement between tracheids and vessels?

  • Tracheids: twisting path, less efficient
  • Vessels: straight path, more efficient
• What shape are tracheids?

  Spindle-shaped
• What is the significance of the twisting path of water in tracheids?

  • Less efficient water transport
  • Contributes to angiosperms' dominance