Answer:
Radioactive isotopes are unstable and will decay. ... The isotopes will decay into a stable isotope over time. Scientists can tell how old the rock was from looking at the radioactive isotope's half-life, which tells them how long it would take for there to be half the radioactive isotope and half the stable isotope.
Answer:
The water cycle
Explanation:
All our sources of fresh water, like rivers, wells, and aquifers, are dependent on <u>the water cycle</u> to replenish and maintain themselves.
Leaders are greedy for more power and land, a large population requires more food, neighbors are becoming to strong
Answer: The name Austria derives from a Germanic word 'austro' which means 'east'.
