The process by which water moves up the xylem against gravity is mainly due to: MCQ with Answer and Explanation

The process by which water moves up the xylem against gravity is mainly due to:
A. Transpiration-cohesion-tension
B. Capillarity
C. Root pressure
D. Active pumping
Answer: Option A
Solution (By JKExamLibrary)
The cohesion-tension theory states that transpiration from leaves creates tension, pulling water up the xylem; water molecules cohere, forming a continuous column. Root pressure is minor.

Discuss this Question (0)

No comments yet. Be the first to start the discussion!

Practice More Biology Questions

Question #1
Consider statements about plant biology: 1. Xylem vessels are dead at maturity. 2. Phloem sieve tubes are living at maturity. 3. Cambium is responsible for primary growth. Which are correct?
A. 1 and 3 only
B. 1 and 2 only
C. 1, 2 and 3
D. 2 and 3 only

Correct Answer: Option B


Explanation:
Xylem vessels and tracheids are dead, hollow cells at functional maturity, providing a continuous tube for water transport. Phloem sieve tube elements are living cells at maturity, though they lack a nucleus, and are responsible for transporting organic nutrients. Cambium (vascular and cork) is a lateral meristem responsible for secondary growth (increase in girth), while apical meristems are responsible for primary growth (increase in length). Thus, statements 1 and 2 are correct.

This question belongs to: Science Biology
Question #2
Which of the following is an example of a Bryophyte?
A. Spirogyra
B. Funaria
C. Fern
D. Pinus

Correct Answer: Option B


Explanation:
Bryophytes are non-vascular land plants that include mosses, liverworts, and hornworts. Funaria is a common moss and a classic example of a bryophyte. Spirogyra is a green alga, ferns are pteridophytes (vascular cryptogams), and Pinus is a gymnosperm.

This question belongs to: Science Biology
Question #3
Consider statements about human anatomy: 1. The heart pumps blood throughout the body. 2. The lungs exchange oxygen and carbon dioxide. 3. The kidneys produce urine. Which are correct?
A. 1, 2 and 3
B. 1 and 3 only
C. 1 and 2 only
D. 2 and 3 only

Correct Answer: Option A


Explanation:
The heart is a muscular pump that circulates blood through the cardiovascular system, delivering oxygen and nutrients to tissues and removing waste. The lungs are the primary organs of the respiratory system, where gas exchange occurs: oxygen diffuses from the alveoli into the blood, and carbon dioxide diffuses from the blood into the alveoli to be exhaled. The kidneys are the primary excretory organs, filtering blood to remove metabolic waste, excess water, and ions, producing urine. All statements are correct.

This question belongs to: Science Biology