Question

Soil compaction results from _______.

Answer 1

Answer;

-All the above

• the reduction or elimination of pore space in soil
• the weight of heavy machinery on soil
• livestock walking over soil

Explanation;

-Soil compaction is a process in which the soil, which is consisted of air and water particles, is reduced to some extent by applying weight. This process involves removing air from the soil particles without any significant change in the amount of water consisted in the soil.

-It is very important because it provides the necessary flat base which provides the crucial support for the buildings, various construction foundations, roads, pavements and any other construction structures.The process of compaction gives the soil higher resistance and greater stability.

Answer 2

Choices on the given question are as follows:
a.the reduction or elimination of pore space in soil
b.the weight of heavy machinery on soil
c.livestock walking over soil
d.all of the above

The answer is letter is letter d. all of the above. 
Soil compaction happens when the soil particles are pressed together, reducing pore space between them. Wheels of heavy machinery like tractors is one of the major causes of soil compaction.