What is the best description of an open system?

The speed of light is around 6.706×10^8 miles per hour. what is the speed of light in units of miles per minute?

How many mmols of tris-hcl are there in 100 ml of a 100 mm tris-hcl buffer solution at ph 8.1? note that the 100 mm refers to the sum of tris and tris-hcl concentrations?

Geothermal energy for industrial use is available almost anywhere. a.true b.false