The system shows is at 20°C. Determine the height h of water in the left side. (SG: specific gravity)​

this allows people to make the best decision or pursue the best option. when alternatives are weighed using their advantages and disadvantages, the option whose disadvantages outweigh the advantages (based on a qualitative or quantitative analysis) are shunned while those whose advantages outweigh their disadvantages are pursued.  

so easy. just google the electromagnetic waves and it’ll pop up.