Which of the Following Best Describes the Role of Biological

Which of the following best describes the role of biological activity in soil development?

A) Plant roots provide channels for air and water movement in soils.
B) Broadleaf trees tend to increase the alkalinity of soil,whereas needleleaf trees increase the acidity.
C) Earthworms increase soil porosity and contribute to soil movement and organic content.
D) All organisms living in,on,and over the soil,influence soil development and characteristics: they can influence the pH,the organic matter,chemical content,and biological content of soils.