(A) Oxygen
(B) Carbon dioxide
(C) Nitrogen
(D) Halogen

(A) weak vocal cords

(B) lower frequency

(C) high frequency

(D) smaller vocal cord

(A) Electric-volt

(B) Erg

(C) Joule

(D) Calorie

(A) Carbohydrate

(B) Protein

(C) Fat

(D) Amino acids

(A) Sulfur Dioxide and Potassium Nitrate

(B)Sulfur and Charcoal

(C) Nitrogen Oxide and Potassium Nitrate

(D) Sulfur Dioxide and Nitrogen Oxide

(A) Capillary action
(B) Atmospheric pressure
(C) Viscosity of oil
(D) Change in temperature

(A) Tungsten
(B) Graphite
(C) Chromium
(D) Nichrome

(A) A decrease in the rate of photosynthesis
(B) An increase in the rate of photosynthesis
(C) A decrease in the rate of respiration
(D) No effect on either photosynthesis or respiration

(A) Water expands on freezing
(B) Bottle contracts at freezing point
(C) the temperature outside the bottle is less than that inside the bottle.
(D) None of the above

(A) Prop him up if he falls
(B) Spread out his weight and reduce the pressure on the rope
(C) Add extra weight to keep the rope tightly stretched
(D) To keep the Center of gravity always above vertically above the rope