Consider the following statements associated with Malaria : 1. Only the female Anopheles mosquitoes take human blood for reproduction 2. Plasmodium can pass across the placenta from mother to foetus Which of the statements given above is/are correct ?
- A.1 only
- B.2 only
- C.Both 1 and 2
- D.Neither 1 nor 2
Correct answer
Explanation
The correct answer is C, Both 1 and 2. Female Anopheles mosquitoes bite humans because they need blood to mature their eggs, and the malaria parasite can cross the placenta.
Malaria is caused by the protozoan Plasmodium, with P. falciparum causing the most dangerous form and P. vivax the most widespread one in India. Male mosquitoes feed only on plant juices and nectar, so they never spread the disease; only the blood-feeding female Anopheles carries the sporozoites into a person. When a pregnant woman is infected, parasites in her blood can cross the placenta and infect the baby, a condition called congenital malaria. Malaria in pregnancy also causes anaemia and low birth weight.
Option A is wrong because statement 2 is also correct. Option B is wrong because statement 1 is also correct. Option D is wrong because both statements describe real features of malaria.
Exam tip: malaria = Plasmodium (protozoan) spread by the female Anopheles; dengue and chikungunya = viruses spread by Aedes.
Practice Questions
View allThe valency of phosphorus is
- A.2, 3
- B.3, 4
- C.4, 5
- D.3, 5
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Phosphorus has five electrons in its outer shell and shows two common valencies, 3 and 5. Phosphorus, atomic number 15, has the electronic configuration 2, 8, 5.
Read the full explanation →Which one of the following statements is NOT correct ?
- A.Single celled eukaryotes belong to Kingdom Protista
- B.Yeast, a fungus is multicellular
- C.The fungi constitute a unique kingdom of heterotrophs
- D.Ascomycetes, a saprophytic fungi is multicellular or rarely unicellular
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This statement is false, because yeast is one of the few fungi that are unicellular. In Whittaker's five-kingdom system, fungi form a separate kingdom.
Read the full explanation →Desalination of seawater is done by using reverse osmosis. The pressure applied to the solution is
- A.larger than osmotic pressure
- B.smaller than osmotic pressure
- C.equal to osmotic pressure
- D.equal to atmospheric pressure
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Read the full explanation →Which one of the following does not form oxide on reaction with oxygen?
- A.Magnesium
- B.Lead
- C.Tin
- D.Silver
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Silver sits near the bottom of the reactivity series and does not combine with oxygen even when heated in air.
Read the full explanation →The foul smell of urine of a healthy man having healthy food, when spilled on floor, is mainly due to the bacterial decomposition of
- A.urea into sulphur dioxide
- B.sugar into carbon dioxide
- C.lipids into methane
- D.urea into ammonia
Show answer
Bacteria on the floor break down the urea in urine and release ammonia, which has a sharp, pungent smell. Urea, CO(NH2)2, is the main nitrogenous waste of humans.
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