Filariasis, leading to elephantiasis, is caused by:
A. Trichinella spiralis
B. Wuchereria bancrofti
C. Ascaris lumbricoides
D. Fasciola hepatica
Answer: Option B
Solution (By JKSSB Mock Tests)
Filariasis, commonly known as elephantiasis due to the severe swelling of limbs and genitals, is caused by filarial worms like Wuchereria bancrofti and Wuchereria malayi. These thread-like nematodes are transmitted by the bite of infected Culex mosquitoes. The adult worms lodge in the lymphatic vessels, causing chronic inflammation and blockage.
Explanation:
Sclerenchyma provides strength, with thick lignified walls; cells are usually dead at maturity. Xylem transports water, phloem transports food, collenchyma is living with uneven thickening.
Explanation:
Gibberellins (GAs) promote stem elongation. In rosette plants (like cabbage, beet, and radish) that have a short stem and closely packed leaves, the application of gibberellin induces sudden and rapid stem elongation just before flowering, a phenomenon known as 'bolting'. This is widely used in agriculture.
Explanation:
Polygenic inheritance is when multiple genes (polygenes) contribute to a single trait, resulting in continuous variation. Human skin color is controlled by at least three genes, showing a spectrum of phenotypes. Pleiotropy is one gene affecting multiple traits. Multiple alleles refer to more than two alleles for a gene (e.g., ABO blood groups). Co-dominance is when both alleles express equally.
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