Consider statements about angiosperms: 1. They have enclosed seeds. 2. They exhibit double fertilization. 3. All angiosperms are trees. Which are correct? MCQ with Answer and Explanation
Consider statements about angiosperms: 1. They have enclosed seeds. 2. They exhibit double fertilization. 3. All angiosperms are trees. Which are correct?
A. 1, 2 and 3
B. 1 and 2 only
C. 2 and 3 only
D. 1 and 3 only
Answer: Option B
Solution (By JKSSB Mock Tests)
Angiosperms are flowering plants where seeds are enclosed within a mature ovary (fruit). They are characterized by double fertilization, where one male gamete fuses with the egg and the other with the secondary nucleus. They exhibit immense diversity in habit, ranging from tiny aquatic Wolffia to massive trees, so not all are trees. Statements 1 and 2 are correct.
Explanation:
The cuticle is a waxy, water-repellent layer secreted by epidermal cells on the outer surface of leaves and young stems. It minimizes water loss through transpiration. Its thickness varies with plant species and habitat; xerophytes often have a thick cuticle. The epidermis is the tissue layer, palisade and spongy mesophyll are photosynthetic tissues.
Consider statements about microorganisms: 1. Penicillin is extracted from a fungus. 2. Streptomycin is extracted from a bacterium. 3. Viruses can be cultured in synthetic media. Which are correct?
Explanation:
Penicillin, the first antibiotic, is extracted from the fungus Penicillium notatum. Streptomycin is an antibiotic derived from the actinomycete bacterium Streptomyces griseus. Viruses are obligate intracellular parasites and cannot be grown or cultured on artificial synthetic media; they require living host cells (like embryonated eggs or cell cultures) to replicate. Thus, statements 1 and 2 are correct.
Explanation:
Pteridophytes (ferns and their relatives) are the first terrestrial plants to possess vascular tissues (xylem and phloem) for water and nutrient transport. However, they do not produce seeds or flowers and reproduce via spores. Hence, they are called 'vascular cryptogams'. Bryophytes are called 'amphibians of the plant kingdom'.
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