1. Renewable energy won’t run out.
2. Maintenance requirements are lower.
3. Renewables save money.
Arteries carry blood away from the heart and veins carry blood back to the heart. Hope that helps (:
First Magnetic Separation to remove the iron fillings.
Next Dissolution of the sand and salt in water, and Filtration to separate the salt solution from the sand.
Evaporation of the salt solution to get back the salt.