If a rock sample has a half-life of 10 years, and has 100 atoms of parent materi today, how many half-lives will have passed before it has only 25 atoms of parent material left Explain your reasoning

Some fossils provide evidence to suggest that earth's climate has changed over time. which information can scientists obtain from these fossils? check all that apply

Imagine you work as a consultant, and your daily job involves listening to the constructive criticism of others. as part of your job, you must listen to opposing viewpoints to make important decisions. in this activity, you are a consulting dam engineer. you must make a decision about four different dams; should they be repaired, taken down, or left alone? you will listen to contrasting opinions about what should be done with the dams before you make the final decision. as the consulting dam engineer, what do you decide to do with this dam? explain your reasoning. by making your decision, did you support the opinions of the mayor and/or the dam safety official? why or why not? (site 1)

What are two australian geographical features that hindered early exploration? western plateau gulf of carpentaria great barrier reef great dividing range