temperatures had to remain above 1 billion degrees in order for atoms to form. b. nebulae condensed and heated to become spinning accretionary disks, then protostars, then stars. c. the process of atom creation, termed Big Bang nucleosynthesis, produced all known natural elements. d. the Earth formed 4.5 billion years ago by the accretion of several small planetesimals.

You have two photos of a person walking. one shows the person at the corner of third and main streets, the other shows the person at the corner of tenth and main streets. there are lampposts at every corner in this town, and the first picture shows it to be 10: 32: 00 exactly. the second picture shows it to be 10: 49: 30. you know three facts: (1) all of the clocks are synchronized; (2) there are exactly 12 equal-sized blocks per kilometer in this town; and (3) the streets that cross main in this area are numbered consecutively, with no interruptions. what is the person’s average speed in kilometers per hour?