What does it mean if the change in mass is a positive number?

Which statement names a chemical property of iron? a: it is dense b: it becomes rusted c: it’s hard to bend d: it has a melting point

How can a geological time scale best be reconstructed? a) comparing vestigial structures in living species b) comparing homologous structures in living species c) examining homologous structures in fossil remains d) examining the written records of scientists from past cultures

This question is only for applicants to scholars for medicine or scholars for dental medicine: what aspects about medicine (or dental medicine) intrigue you? describe how these aspects influence your life. (100-650 words)