Ineed can someone explain this equation to me

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.

Find the area of shaded region z=-0.89

Astudy group should stay around 3-6 people. true or false