Which of the following is the best example of naturalistic observation?.

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.

The occupational safety and health administration requires employers to provide fall protection to construction workers who are working on surfaces with unprotected sides and edges feet or greater above the lower level.

How many liters of 60% alcohol solution should be added to 40 liters of a 20% alcohol solution to make a 50% solution?