How does the level of salinity in ocean water affect marine life?

Which two statements are true about a system? 1. a system is a group of objects analyzed as one unit. 2. energy that moves across system boundaries is conserved. 3. there’s only one way to define the boundaries of a system. 4. all systems are made by humans.

Late at night some traffic signals change patterns and become ?

Which of these international trade concepts results in specialization and trade increases in total world output? a) absolute advantage b) balance of payments c) absolute advantage d) international tariffs