Vinegar is prepared by the

A. Fuming of date palms
B. Fermentation of rotten grapes
C. Fermentation of apple cider in the presence of air
D. Dehydration of wine

Answer

B. Fermentation of rotten grapes

Submitted by: Toheed Ahmed

The twinkling of the stars is due to the reason that

A. The stars do not emit light continuously
B. The refractive index of Earth’s atmosphere fluctuates
C. Intermittent absorption of star; light by Earth’s atmosphere
D. Intermittent absorption of star; light by stars’ atmosphere

Answer

B. The refractive index of Earth’s atmosphere fluctuates

Submitted by: Toheed Ahmed