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प्रश्न
Give biological reasons for the following statements : In some xerophytes leaves are modified into spines
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उत्तर
Xerophytes are plants growing in dry climate. It is important for them to conserve water. Leaves modified into spines reduce the surface area and thus reduce the rate of transpiration.
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संबंधित प्रश्न
Cochlea, Malleus, Pinna, Stapes, Incus.
Complete the following paragraph by filling in the blank (1) to (5) with appropriate words:
To test a leaf for starch, the leaf is boiled in water to (1) _________. It is then boiled in Methylated spirit to (2) ________. The leaf is dipped in warm water to soften it. It is placed in a petri dish, and (3) _____ solution is added. The region of the leaf which contains starch, turns (4) ________and the region while does not contain starch, turns (5) __________.
The figure given below represents the vertical section of a leaf.
( i) Name the parts labeled 1 to 5.
( ii ) What do the two arrows (dotted and solid) indicate in the daytime and at night?
( iii) Could you add one more arrow in the figure? If yes, what for?
( iv) How many leaf veins have been shown in this section?
Identify the false statements and rewrite them correctly by changing the first or last word only.
Algae are autotrophs.
"Oxygen is a waste product of photosynthesis." Comment.
Give technical term:
The main reaction which means the breaking up of water molecules through light.
Column ‘II’ is a list of items related to ideas in Column ‘I’. Match the term in Column ‘II’ with the suitable idea given in Column ‘I’.
| Column I | Column II | ||
| (i) | Grana | (a) | Decomposers |
| (ii) | Autotrophs | (b) | Light reaction |
| (iii) | By-products of photosynthesis | (c) | Animals |
| (iv) | Photolysis | (d) | Oxygen |
| (v) | Bacteria and fungi | (e) | Stimulated by light |
| (vi) | Chloroplast | (f) | Power |
| (vii) | Oxygen and water | (g) | Raw material |
| (viii) | Sunlight | (h) | Machinery |
| (ix) | CO2 and water | (i) | End products |
| (x) | Glucose (sugar) | (j) | Workrooms |
| (xi) | Cells in the leaf | (k) | By-products. |
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Higher Order Thinking Skill.
Imagine that student A studied the importance of certain factors in photosynthesis. He took a potted plant and kept it in dark for 24 hours. In the early hours of the next morning, he covered one of the leaves with dark paper in the centre only. Then he placed the plant in sunlight for a few hours and tested the leaf which was covered with black paper for starch.
- What aspect of photosynthesis was being investigated?
- Why was the plant kept in the dark before the experiment?
- How will you prove that starch is present in the leaves?
- Name the raw materials needed for photosynthesis.
During photosynthesis, plants exhale ______.
