Elements and compounds are pure substances that cannot be broken down physically into a simpler substance. A physical change doesn’t break the bonds between atoms of a substance or form new ones. Compounds can be broken down by a chemical change. A chemical change breaks chemical bonds and/or forms new ones between atoms of a substance. What simple substance would a compound break into? The basic elements that make it up! For example, if you passed a very strong electric current through water you’d break the chemical bonds in water and be left with oxygen and hydrogen. Which of the following is an example of a chemical change? A
separating water into different glasses

B
breaking frozen ice cubes with a hammer

C
running an electric current through water

D
boiling water to evaporate it on a stove

You will create a molecular clock model for an arthropod gene. follow these guidelines to make your model: . your timeline will span from 90 million years ago to the present. the common ancestor in your model is an arthropod that lived 90 million years ago. the gene that you'll track codes for a protein in the species venom . the dna sequence youll track contains 10 nitrogen bases. you can choose the order of the bases and where the mutations occur. this gene mutates at a rate of approximately 0.76 base pairs every 17.1 million years. to build your model,/ calculate the estimated time period it takes for 1 base pair to mutate. the first time period will only show the common ancestor. at the beginning of the second time period, three lineages will diverge from the common ancestor, each with a different mutation in their gene sequences. the first and third descendant species will survive for the rest of the timeline. the second descendant species was extinct 50 million years ago. calculate how long it will take for one full base pair mutation to occur. explain your reasoning by constructing a mathematical equation