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प्रश्न
What is toxicity ?
उत्तर
It refers to the kind of external osmotic environment of a cell or it refers to the type of solution outside the cell.
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संबंधित प्रश्न
Give reason for the following:
If you uproot a plant from the soil, its leaves soon wilt.
Three plants (a), (b) and (c) were placed in beakers containing coloured water. The water in each beaker was covered with a layer of oil. The leaves were removed from plant (b), while plant (c) was exposed to strong light.
(i) In which plant, (a), (b) or (c) would the water move up the fastest?
(ii) In which plant (a), (b) or (c), would the water move up slowly?
(iii) Why was the water covered with a layer of oil?
(iv) What is being investigated by this experiment?
Choose the correct answer:
Exudation or bleeding is associated with ___________
Study the experimental setup in the figure and then answer the question that follow.
What will you observe in the setup after about half an hour? Give reasons for your answer.
Column ‘II’ is a list of items related to ideas in Column ‘I’. Match the term in Column ‘II’ with a suitable idea given in Column ‘I’.
| Column I | Column II |
| (i) Diffusion | (a) The exit or flow of water from the cell to the outer environment. |
| (ii) Xylem | (b) The shrinkage of protoplasm when the cell is kept in a hypertonic solution. |
| (iii) Root pressure | (c) The tissue through which water and mineral salts move upward in a plant. |
| (iv) Isotonic solution | (d) Two solutions which have equal osmotic pressure. |
| (v) Exosmosis | (e) The process by which the molecules of perfume spread in the room when the bottle is open. |
| (vi) Osmosis | (f) The process by which roots absorb water from the soil. |
| (vii) Plasmolysis | (g) The pressure by which water rises up to some feet in a lofty tree. |
| (viii) Hypotonic solution | (h) The concentration of the solution when lower than that of the cell sap. |
Define: Root hair
Trace the pathway followed by water molecules from the time it enters a plant root to the time it escapes into the atmosphere from a leaf.
____________plants like orchids absorb water vapours from air with the help of epiphytic roots having special tissue called velamen.
The unbranched root hair in plants is formed from ____________.
Why and how does water enter continuously into the root xylem?
