Transport In Plants

Step 1: Understanding the process of water absorption.
Water absorption by root hairs occurs in three distinct stages:

Imbibition: This is the initial stage where water is absorbed by hydrophilic substances (e.g., cell wall components like cellulose) through capillary action.

Diffusion: After imbibition, water molecules diffuse from regions of higher concentration (soil solution) to lower concentration (root hair cells).

Osmosis: Finally, water moves through the semipermeable membranes of root hair cells into the root cortex via osmotic gradients.

Step 2: Explanation of the correct sequence.
The correct sequence in water absorption is: Imbibition occurs first as the cell walls absorb water. Diffusion facilitates water movement to the root hair cytoplasm. Osmosis enables water transport across membranes into deeper root cells.

Step 3: Explanation of other options.
Option (B): Incorrect. Osmosis does not occur first; imbibition precedes it.

Option (C): Incorrect. Diffusion does not occur before imbibition.

Option (D): Incorrect. Osmosis occurs after diffusion, not before.

The correct word to fill in the blank is "transpired". Transpiration is the process by which water is lost from a plant through evaporation from the plant's leaves, primarily through stomata.
Water that is transpired is lost into the atmosphere and is not absorbed by the plant.
- "Evaporated" could also be associated with water loss but typically refers to the transition of water from a liquid to a gas.
- "Absorbed" and "diffused" both suggest processes where water is taken in by the plant, which contradicts the context of the sentence.

Thus, the correct answer is option (A), as it refers specifically to water lost and not absorbed by the plant.