831. What is the common name for the drug acetyl salicylic acid?
A. Paracetamol
B. Analgin
C. Aspirin
D. Penicillin

832. The sounds of which frequency are human beings most sensitive?
A. 400 hertz
B. 20 hertz
C. 20000 hertz
D. 5000 hertz

833. On which disease did Robert Koch work?
A. Tuberculosis
B. Cholera
C. Malaria
D. Diabetes

834. Which of the following gases do plants and trees give out during photosynthesis?
A. Hydrogen
B. Nitrogen
C. Oxygen
D. Carbon dioxide

835. Which of the following is not a waterborne disease?
A. Cholera
B. Amoebiasis
C. Typhoid
D. Influenza

836. Name the branch of science which deals with the study of sound and sound waves?
A. Aeronautics
B. Acoustics
C. Aerostatics
D. Aetiology

837. Which metal is added to steel to make it stainless steel?
A. Chromium
B. Aluminium
C. Carbon
D. Copper

838. What is the range, in hertz, of the normal human hearing?
A. 10 Hz to 10 kHz
B. 20 Hz to 20 kHz
C. 2000Hz
D. 40 Hz to 40 kHz

839. Who invented Logarithm Tables?
A. John Napier
B. John Doe
C. John Harrison
D. John Douglas

840. How many pairs of walking legs does a cockroach have?
A. One
B. Two
C. Three
D. Four