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General ScienceEasyAsked in: CDS · CDS-II 2022, GK

Deficiency of iron causes

  1. A.Anaemia
  2. B.Scurvy
  3. C.Rickets
  4. D.Cholera

Correct answer

A. Anaemia

Explanation

The correct answer is A, Anaemia. Iron is needed to make haemoglobin, so too little iron means too little haemoglobin and a reduced ability of the blood to carry oxygen.

Haemoglobin is the iron-containing protein in red blood cells that picks up oxygen in the lungs and delivers it to the tissues. When the diet lacks iron, or iron is lost through bleeding, the body makes fewer and smaller red cells with less haemoglobin. The person feels tired and breathless, and looks pale. Iron-deficiency anaemia is the most common nutritional deficiency in India, especially among women and children; green leafy vegetables, jaggery, pulses, meat and iron-folic acid tablets help prevent it.

Option B is wrong because scurvy is caused by a lack of vitamin C. Option C is wrong because rickets is caused by a lack of vitamin D. Option D is wrong because cholera is a bacterial infection caused by Vibrio cholerae, not a deficiency disease.

Exam tip: iron, anaemia; iodine, goitre; vitamin C, scurvy; vitamin D, rickets.

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Q3.General ScienceAsked in: CDS · CDS-I 2026, GKMedium

Consider the following statements regarding waves : 1. If the particles of a medium move along the direction of motion of the wave, the wave is called a longitudinal wave. 2. If the particles of a medium move perpendicular to the direction of motion of the wave, the wave is called a transverse wave. 3. Transverse waves may involve change in the shape of the medium, whereas longitudinal waves involve change in the density of the medium. Which of the statements given above is/are correct ?

  1. A.1 and 2 only
  2. B.1 only
  3. C.2 and 3 only
  4. D.1, 2 and 3
Show answer
Correct answer: D. 1, 2 and 3

All three statements correctly describe how particles move in the two kinds of mechanical waves. In a longitudinal wave, such as sound in air, the particles vibrate back and forth along the direction in which the wave travels.

Q5.General ScienceAsked in: CDS · CDS-I 2017, GKMedium

When a piece of pure silicon is doped with aluminium, then

  1. A.the conductivity of the doped silicon piece will remain the same
  2. B.the doped silicon piece will become n-type
  3. C.the doped silicon piece will become p-type
  4. D.the resistivity of the doped silicon piece will increase
Show answer
Correct answer: C. the doped silicon piece will become p-type

Aluminium has three valence electrons, one fewer than silicon, so each aluminium atom leaves a hole that acts as a positive charge carrier.