Which one of the following is the scientific name of the causal organism of elephantiasis?
- A.Ascaris lumbricoides
- B.Culex pipiens
- C.Wuchereria bancrofti
- D.Fasciola hepatica
Correct answer
Explanation
The correct answer is C, Wuchereria bancrofti. This filarial roundworm causes elephantiasis, also called lymphatic filariasis.
The adult worms live in the lymphatic vessels and block the flow of lymph, so the legs, arms or genitals swell and the skin thickens, giving the disease its name. The tiny larvae, called microfilariae, circulate in the blood and are picked up by the female Culex mosquito, which passes them on to the next person it bites. Brugia malayi causes a similar disease. India runs mass drug administration campaigns to stop its spread.
A, Ascaris lumbricoides, is the common intestinal roundworm that causes ascariasis, spread through contaminated food and water.
B, Culex pipiens, is a mosquito, the carrier (vector) of the filarial worm, not the organism that causes the disease.
D, Fasciola hepatica, is the liver fluke that infects the liver of sheep and cattle.
Exam tip: filariasis, Wuchereria bancrofti, spread by the Culex mosquito; malaria, Plasmodium, spread by the Anopheles mosquito.
Practice Questions
View allThe principle involved in paper chromatography is
- A.Absorption
- B.Partition
- C.Solubility
- D.Volatility
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Paper chromatography separates substances because each one divides, or partitions, itself differently between two liquid phases. In paper chromatography the stationary phase is the water held in the cellulose fibres of the paper, and the mobile phase is the solvent that rises up the paper by capillary action.
Read the full explanation →Which one of the following phenomena CANNOT be exhibited by sound waves ?
- A.Reflection
- B.Refraction
- C.Interference
- D.Polarisation
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Sound in air is a longitudinal wave, and only transverse waves can be polarised. Polarisation means restricting the vibrations of a wave to a single plane.
Read the full explanation →Which one of the following is NOT a luminous object ?
- A.Sun
- B.Electric lamp
- C.Candle
- D.Moon
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The Moon gives out no light of its own; it only reflects sunlight, so it is a non-luminous object. A luminous object produces and emits its own light, while a non-luminous object is seen only because it reflects light falling on it.
Read the full explanation →In experiment #1, a bar magnet is moved towards a conducting wire loop axially, with the magnet's north pole facing the loop. In experiment #2, the same process as in experiment #1 is repeated except that the south pole of the magnet faces the loop. Which one of the following statements is true in this context?
- A.The direction of current in the loop will be of opposite nature in both the experiments.
- B.The direction of current in the loop will be the same in both the experiments.
- C.No current will flow in either of the two experiments.
- D.More current will flow in the loop in experiment #1.
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Reversing the pole that approaches the loop reverses the change in magnetic flux, so the induced current reverses too. When a magnet moves towards a closed loop, the magnetic flux through the loop changes and an electric current is induced (Faraday's law of electromagnetic induction).
Read the full explanation →Which one of the following statements about classification of plants is correct?
- A.Thallophytes have well differentiated body design
- B.Funaria is a fungus
- C.All Pteridophytes are Phanerogams
- D.Vascular system is not found among Bryophytes
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Mosses and liverworts have no xylem or phloem, so water moves through them cell to cell. Bryophytes, such as Funaria (a moss) and Marchantia (a liverwort), are called the amphibians of the plant kingdom because they live on land but need water for fertilisation.
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