What happened around 500 million years ago?

substitution is the answer in this case

measuring physical properties lab reportinstructions: in the physical properties lab, you will test the physical properties of different building materials in order to pick the appropriate materials for a new home in tiny world. record your observations and test measurements in the lab report below. youwill submit your completed report.name and title: lyric lawton, mr.herbert, 10/13/17, physical properties lab. objective(s): i need to parvus build his house out of the right material, so he will stay cool in the mountains.hypothesis: if we use wood to build the roof of the house, then the temperature inside the house will remain cooler.if we use clay brick to build the walls and floors of the house, then the temperature inside the house will remain cooler.if we use aluminium to bring electricity into the home, then it will allow electricity to flow into the home at a faster rate.if we use iron to construct the latches on the windows and doors, then the magnetism will keep the latches secure.