991. Adult human brain is about_________% of the total body weight.
A. 2%
B. 3%
C. 7%
D. 8%

992. Which of the following is the hardest substance?
A. Copper
B. Diamond
C. Iron
D. Silicon

993. Which one of the following is also called Stranger Gas?
A. Neon
B. Argon
C. Xenon
D. Nitrous oxide

994. Which of the following disease is spread by Fleas?
A. Small pox
B. Tetnus
C. Typhus
D. Yellow fever

995. According to many, including the Guinness Book of World Record,________is the world’s rarest mineral?
A. Painite
B. Benitoite
C. Jadeite
D. Taaffeite

996. Which stone floats on water?
A. Pumice stone
B. Lime stone
C. Basalt stone
D. Quartzite stone

997. How many layers of Atmosphere?
A. 2
B. 3
C. 4
D. 5

998. Why normal rain is slightly acidic?
A. due to presence of dust in air
B. carbon dioxide and water in clouds react to form carbonic acid
C. Ozone depletion
D. All of these

999. Disolved oxygen (DO) in water should be?
A. 400 to 800 ppm
B. 4000 to 8000 ppm
C. 0.4 to 0.5 ppm
D. 4 to 5 ppm

1000. As a result of which treaty, ozone hole in Antarctica is slowly healing?
A. Koyoto protocol
B. Ottawa treaty
C. Montreal protocol
D. Oslo Accord