6. What is involved in the formation of carbonic acid as the primary ageni of chemical weathering?
A. plant roots
b. oxygen reacting with iron compounds c. carbon dioxide dissolving in rainwater d. bacteria that feed on plani and animal remains
7. How is weathering useful to us?
A. Weathering of rocks helps to form the basic component of soil
b. Weathered rocks mixed with minerals are richer in mineral diversity and contributes to more fertile soil.
c. li is the mechanism by which one of the planei's most imporiani natural resources is formed and that is the soil.
d. All of the above.
8. What type of weathering is manifested when burrowing animals bring materials to the surface to be exposed to the agents of weathering?
A. biological weathering
C. physical weathering
B. chemical weathering
D. mechanical weathering
9. What is the first siep in the production of soils?
a. erosion
B. hydrolysis
C. transportation
D. weathering
10. What is humus? Humus is composed of____
a. tiny particles in the soil
b. rock materials where the soil comes from
c. residue of decayed plants and animals D. particles of soil which are grouped into three
11. Which of the following fill up the spaces between soil particles?
A. clay and silt
C. sand and clay
B. water and air
D. humus and weathered rocks​