276: Lead, ingested or inhaled, is a health hazard. After the addition of lead to petrol has been banned, what still are the sources of lead poisoning?
1. Smelting units
2. Pens and pencils
3. Paints
4. Hair oils and cosmetics
Select the correct answer using the codes given below :
(a) 1, 2 and 3 only
(b) 1 and 3 only
(c) 2 and 4 only
(d) 1, 2, 3 and 4
277: The diameters of two circular coins are in the ratio of 1:3. The smaller coin is made to roll around the bigger coin till it returns to the position from where the process of rolling started. How many times the smaller coin rolled around the bigger coin ?
(A) 9
(B) 1.5
(C) 6
(D) 3
278: Which of the following Constitution Amendment Acts seeks that the size of the Councils of Ministers at the Centre and in a State must not exceed 15 per cent of the total number of members in the Lok Sabha and the total numbers of members of the Legislative Assembly of that state respectively ?
(a) 91 st
(b) 93 rd
(c) 97 th
(d) 95th
279: The maturity of a river course is recognised by the presence of
(a) V-shaped valley
(b) Meanders
(c) Gorges
(d) High denudational power
280: Which of the following two continents are just like the mirror images of each other?
(a) South America and Africa
(b) South America and North America
(c) South America and Australia
(d) Europe and Asia