Answer: a. permeable
Explanation:
Permeable is the ability of the substance to transmit substances through it.thus soil transmits water as it permeable which is due to the presence of pores in it.
Horizontal refers to parallel to the plane of the horizon which is at right angles to the vertical.
Biotic refers to all the living components of the system.
Aggregate refers to a material or structure formed from a loose mass of fragments or particles.
