Which metal pollute the air of a big city?
Which metal pollute the air of a big city?
	A. Copper
B. Chromium
C. Lead
D. Cadmium
A. Copper
B. Chromium
C. Lead
D. Cadmium
A. Medicine
B. Fertilizer
C. Salt
D. Glass
A. oxygen and hydrogen
B. oxygen, hydrogen, acetylene and nitrogen
C. oxygen, acetylene and argon
D. oxygen and acetylene
A. Methane
B. Nitrous oxide
C. Carbon dioxide
D. Hydrogen
A. Blood
B. Lungs
C. Kidney
D. pancreas
A. Sodium nitrate
B. Zinc sulfate
C. Sulphuric acid
D. Calcium carbonate
A. 100
B. 400
C. 1000
D. 4000
A. ease the process of cooking
B. increase the taste
C. produce small amount of hydrochloric acid required for digestion
D. inclease solubility of food particles in water
A. Lens
B. Prism
C. Mirror
D. Slabs
A. light waves on it
B. microwaves on it
C. radio waves on it
D. ultra high frequency waves on it