What prevents the earth’s atmosphere from drifting away into space?

A. Summer
B. Winter
C. Spring
D. Autumn

In humans , most nutrient molecules are absorbed by the ?

A. Small intestine
B. Stomach
C. Liver
D. Large intestine
E. None of these

A. Vitamins
B. minerals
C. Carbohydrates
D. None of these

Muscle fatigue is caused by the accumulation of___________?

A. Uric acid
B. Lactic acid
C. Oxalacetic acid
D. Fyruvie acid

A. X
B. K
C. J
D. N

A. Iodine
B. Potassium
C. Sodium Chloride
D. Chlorine