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 scientist from past structures.

C.

This makes the most sense to me. Studying fossils is how it is usually done. Many things can be told from this.

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.