Question

A vascular element "A" is dead, cylindrical, lignified and conduct substances due to a negative pressure created in it due to transpiration pull. A vascular element "B" is living, cylindrical, non lignified, enucleated and conduct substances due to a positive pressure created in it. A & B conducting elements respectively are

• A. xylem parenchyma & sieve tubes
• B. xylem vessels & sieve tubes
• C. sieve tubes & xylem tracheids
• D. sieve tubes & xylem vessels

Answer 1

The correct option is B xylem vessels & sieve tubes

Xylem vessels are dead cylindrical, lignified and conduct substances due to a negative pressure created in it due to transpiration pull.

Sieve tube is a living, cyclindrical, non lignified and enucleated vascular element. They transport substances due to positive pressure.