Bleeding of gums, falling of teeth, fragile bones and delayed wound healing occur due to the deficiency of which one of the following vitamins?
- A.Vitamin C
- B.Vitamin K
- C.Vitamin D
- D.Vitamin B
Correct answer
Explanation
The correct answer is A, Vitamin C. These are the signs of scurvy, the disease caused by a lack of vitamin C (ascorbic acid).
Vitamin C is needed to make collagen, the protein that holds together gums, skin, blood vessels and bone. Without it, gums swell and bleed, teeth loosen and fall, small blood vessels break and wounds heal slowly. Sailors on long voyages once suffered from scurvy until citrus fruits were added to their diet. Amla, lemons, oranges and guava are rich sources, and the vitamin is easily destroyed by heat.
B is wrong: vitamin K deficiency delays blood clotting.
C is wrong: vitamin D deficiency causes rickets in children and osteomalacia in adults.
D is wrong: B vitamins cause other diseases, such as beriberi (B1) and pellagra (B3).
Exam tip: C-scurvy, D-rickets, K-clotting, A-night blindness, B1-beriberi.
Practice Questions
View allWhich of the following properties is true for a tooth paste?
- A.It is acidic
- B.It is neutral
- C.It is basic
- D.It is made up of Calcium phosphate, the material of tooth enamel
Show answer
Toothpaste is mildly basic so that it can neutralise the acid that causes tooth decay. Bacteria in the mouth break down sugar and food particles left on the teeth and produce acids.
Read the full explanation →A stainless steel chamber contains Ar gas at a temperature T and pressure P. The total number of Ar atoms in the chamber is n. Now Ar gas in the chamber is replaced by CO₂ gas and the total number of CO₂ molecules in the chamber is n/2 at the same temperature T. The pressure in the chamber now is P'. Which one of the following relations holds true? (Both the gases behave as ideal gases)
- A.P' = P
- B.P' = 2P
- C.P' = P/2
- D.P' = P/4
Show answer
For an ideal gas in a fixed volume at a fixed temperature, pressure is proportional to the number of molecules, so half the molecules give half the pressure.
Read the full explanation →In which of the following pairs are the ions isoelectronic?
- A.Mg²⁺, Ar
- B.Na⁺, O²⁻
- C.Al³⁺, Cl⁻
- D.K⁺, Ne
Show answer
Both have 10 electrons, the same number as a neon atom, so they are isoelectronic. Isoelectronic species have the same number of electrons.
Read the full explanation →A solid disc and a solid sphere have the same mass and same radius. Which one has the higher moment of inertia about its centre of mass?
- A.The disc
- B.The sphere
- C.Both have the same moment of inertia
- D.The information provided is not sufficient to answer the question
Show answer
About an axis through the centre, a solid disc has I = ½MR² while a solid sphere has I = ⅖MR², and ½ is larger than ⅖.
Read the full explanation →Numerically two thermometers, one in Fahrenheit scale and another in Celsius scale shall read same at
- A.−40°
- B.0°
- C.−273°
- D.100°
Show answer
At this one temperature the Celsius and Fahrenheit scales show the same number. The two scales are linked by F = (9/5)C + 32.
Read the full explanation →