18.Which shows chemical weathering? A. Rocks are dissolved by acid.
B. Rocks are irregularly shaped.
C. Rocks are broken into pieces.
D. Rocks are changed into finer particles.

19. How long does it take for the moon to rotate on its axis?
A. 12 days
B. 20 days
C. 15 days
D. 28 days

20.Why is the moon important to human beings?
A. It help farmer know the right time to plant crops.
B. It makes planet earth beautiful.
C. It makes the earth climates bearable.
D. It makes earth a more livable planet and stay in its axis.

22.Which statement is NOT true?
A. Stars differ in size.
B. Red stars are the hottest star.
C. The sun is a medium sized yellow star.
D. Supernovas are exploding stars.

24.What is the effect of the northeast monsoon in the country?
A. Brings rainfall.
B. Cold weather and little rainfall.
C. No rainfall and cold weather.
D. Little rainfall and warm weather.