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.
Answer:
High-Pressure Center
Explanation:
To get this answer, this question and answer is based on the <em>Coriolis effect</em>. The <em>Coriolis effect</em> causes the air to rotate in a clockwise direction. When it turns clockwise direction, it will always be high pressure.
No they cant be mechanical because then something would have to generate their rays through the inventing of a machine.