Answer:
Fibrous
Explanation:
Proteins are assembled according to their functions. Fibrous proteins usually provide protection and support to cells. They are made up of polypeptides that have elongated shape and assembles in large cables or threads. These proteins are differentiated from globular proteins by their globular form and repeated units of amino acids.
For example the fibrous proteins involved in horns, hair and nails is alpha-keratin. Elastin found in skin and ligament is also a fibrous protein. Collagen includes collagen fibrils that have tensile strength of steel is also a fibrous protein found in cartilages and bones.
Material through which water flows is permeable. This material can be either natural or artificial. Naturally permeable material can be clean sand and gravel for example, or a sandstone and in the latter case the sandstone can have both porosity which is not synonymous with permeability as the pores must be connected to be permeable. An impermeable membrane could be used to line ditches for example to prevent leakage near mines.
