521: Lothal is
(a) A closed water system
(b) A poisonous gas
(c) A place in Gujarat where excavations have established a link with the Indus Valley civilisation
(d) Legal action taken against defectors
522: Human activities in the recent past have caused the increased concentration of carbon dioxide in the atmosphere, but a lot of it does not remain in the lower atmosphere because of
1. Its escape into the outer strato-sphere.
2. The photosynthesis by phyto-plankton in the oceans.
3. The trapping of air in the polar ice caps
Which of the statements given above is/are correct?
(a) 1 and 2
(b) 2 only
(c) 2 and 3 only
(d) 3 only
523: Under the administration of which one of the following is the Department of Atomic Energy?
(a) Prime Minister's Office
(b) Cabinet Secretariat
(c) Ministry of Power
(d) Ministry of Science and Technology
524: Recently, there has been a concern over the short supply of a group of elements called 'rare earth metals'. Why?
1. China, which is the largest producer of these elements, has imposed some restrictions on their export.
2. Other than China, Australia, Canada and Chile, these elements are not found in any country.
3. Rare earth metals are essential for the manufacture of various kinds of electronic items and there is a growing demand for these elements.
Which of the statements given above is/are correct?
(a) 1 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3
525: Consider the following statements:
1. The first telegraph line in India was laid between Kolkata (formerly Calcutta) and Diamond Harbour.
2. The first Export processing zone in India was set up in Kandla.
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