Is a burning log an exothermic or endothermic event if the log is the system?

Which substances have the lowest melting points: ionic covalent, or metallic

Using data from seismic waves, geologists have learned that earth’s interior is made up of several

Mike and mitchell decide to have a foot race. they mark off a stretch of 100 yards, and recruit cindy to work the stopwatch. after running the race and looking at the results, cindy declared that mitchell was the fastest. so how did the boys times compare?