State any two characteristics of the tapetum, present in the microsporangium of an angiosperm. Why are non-viable pollen grains seen to develop in a microsporangium where tapetum is damaged or under developed ? Give a reason.
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When and where does reduction division take place in the life cycle of a liverwort, a moss, a fern, a gymnosperm and an angiosperm?
Liverwort – In liverworts, the main plant-body is haploid (gametophytic). It bears the male and female sex organs which produce gametes. These gametes fuse to form a zygote. The zygote...
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Explain the role of tapetum in the formation pollen-grain wall.
Tapetum is the innermost layer of the microsporangium. It provides nourishment to the developing pollen grains. During microsporogenesis, the cells of tapetum produce various enzymes, hormones, amino acids, and other...
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Shobo’s mother’s present age is six times Shobo’s present age. Shobo’s age five years from now will be one third of his mother’s present age.
At present, _________ Shobo's age = x years His mother's age = 6 times of Shobo's age = 6x years Five years from now ________________ Shobo's age = ( x + 5 ) years According to the problem given, x...
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Mention any three iron ore- belts of India? Write any three characteristics of the southern most iron ore belt .
1. Odisha-Jharkhand Belt- Famous for Haematite iron ore. Badampahar Mines in the Mayurbhanj and Kendujhar districts. Singhbhum district of Jharkhand. 2. Durg-Bastar-Chamdarapur Belt- High Grade Haematite ore. Chhatisgarh and Maharashtra.Bailadadila range...
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Mention any three iron ore- belts of India? Write any three characteristics of the southern most iron ore belt .
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Define receptor and state their location in our body. Mention any two receptors present in our forebrain and their functions.
(i) Specialised tips of some nerve cells which receive information from the surroundings. Location: Sense organs Gustatory receptor: detect a taste Olfactory receptor: detect a smell (ii) The information acquired at the end of...
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Seema’s present age is four times her son’s present age and four-seventh of her father’s present age.
(b) Let Seema’s present age be x years. Then, Seema’s son’s present age = x/4 years Seema’s father’s present age = 7x/4 years. Then, x+ x/4 +7x/4= 32x3 12x = 96 × 4 x = 96...
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The outermost and innermost wall layers of microsporangium in an anther are respectively:
d. Epidermis and tapetum
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Present a classification of colloids where dispersion medium is water. State the characteristics and one example of each of these classes.
When the dispersion medium is water colloids are classified as hydrophilic colloids and hydrophobic colloids. Hydrophilic colloids are solvent (water) attracting, reversible and quite stable, e.g., gum, starch, gelatin etc....
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A bilobed, dithecous anther has 100 microspore mother cells per microsporangium.
The bilobed anther can produce 1600 male gametophytes.
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