The solar system is considered a natural system because it was made and controlled by natural forces, meaning, it was never influenced with human creations. It is considered as one of the products of the phenomenon of the physical world. Hope this answer helps you.
If I am correct it is The Third Trimester
<span>Sputum membranes tests are used to test the lungs, trachea and bronchial canals for pathogens that can have an adverse affect on the lungs. These pathogens can cause infections that can have serious effects on your breathing and all over health.</span>