2516: Biological Oxygen Demand (BOD) is a standard criterion for
(a) Measuring oxygen levels in blood
(b) Computing oxygen levels in forest ecosystems
(c) Pollution assay in aquatic ecosystems
(d) Assessing oxygen levels in high altitude regions
2517: A fertile-soil, suitable for growing common crops, is likely to have a pH value of
(a) three
(b) four
(c) six to seven
(d) nine to ten
2518: Which arrangement of the following show the correct sequence of demographic transition as typically associated with economic development?
I. High birth rate with high death
II. Low birth rate with low death
III. High birth rate with low death
Choose the answer from the codes given below :
Codes:
(a) I, II, III
(b) I, III, II
(c) III, I, II
(d) II, I, III
2519: Which one of the following important trade centres of ancient India was on the trade route connecting Kalyana with Vengi ?
(a) Tagara
(b) Sripura
(c) Tripuri
(d) Tamralipti
2520: The head of the military department under the reorganised central machinery of administration during Akbar's reign was
(a) Diwan
(b) Mir Bakshi
(c) Mir Saman
(d) Bakshi