Transpiration is defined as:

1. the rise of water up to the stem of a plant.
2. the elimination of water with dissolved water products.
3. the loss of water as water vapour from the aerial parts of a plant.
4. the loss of water as water vapour from the roots as well as the leaves of the plant.

Which one of the following favours the fastest transpiration rate?

1. A cool, humid, windy day,
2. A hot, humid, windy day,
3. A hot, humid, still day,
4. A hot, dry, windy day.

Root hairs are the epidermal outgrowths of the outermost layer of roots. They are well-suited for absorption of water from soil due to which of the following features ?

P. Large surface area.
Q. Lower concentration of cell sap.
R. Semi permeable nature of the cell membrane.

1. Only P
2. Only Q
3. Only P and Q
4. Only P and R

Xylem tissue forms a tubular passage to transport water and mineral salts from the roots to the aerial parts of a plant. It consists of different types of cells.

P. Sieve tubes and companion cells
Q. Wood parenchyma and wood fibres
R. Tracheids and vessels

Which of the following are xylem components?

1. Only P
2. Only P and R
3. Only Q and R
4. All P, Q and R