291. The heaviest naturally-occurring element is_________?
A. Radium
B. Platinum
C. Uranium
D. Cadmium

292. The heaviest man made element found so for is__________?
A. Promethium
B. Ununoctium
C. Francium
D. Technetium

293. Which instrument is used for viewing the sun?
A. Stroboscope
B. Heliograph
C. Solograph
D. None of these

294. ___________ is a strong smelling agent added to LPG cylinders to detect leakage?
A. Nitrogen Peroxide
B. Ethyl Mercaptan
C. Carbon Monoxide
D. Sulphur Dioxide

295. A crescograph is a device for measuring the growth in __________?
A. Micro Organism
B. Plants
C. Human
D. Pollution

296. Which of the following is used in water purification?
A. Reverse Osmosis
B. Osmosis
C. Cytolysis
D. Turgor Pressure

297. lightest metal is__________?
A. Lithium
B. Sodium
C. Magnesium
D. Aluminium

298. Which of the following pollutants in water causes “Minamata disease?
A. Methyl Mercury
B. Lead
C. Salmonella
D. Perchlorate

299. The process of converting wet waste to manure is___________?
A. Metabolism
B. Conservation
C. Incineration
D. Composting

300. Which of the following organisms releases molecular oxygen into water?
A. E.coli
B. Phytoplankton
C. Amoeba
D. Salmonella