Answer:
To check if it's properly cleaned.
Explanation:
When you finish using a microscope, you have to take out all your samples you were using and make sure it is completely clean so that no further contamination affects future sample analysis.
Also when you begin to use it, make sure it is clean so that when you analyze your sample(s) are free from other unexpected agents.
Each isotope has a unique rate of decay, making them suitable for determining the dates of ancient artifacts. The answer is "rate of decay of the isotope."
Alfred Wegener
proposed the continental drift theory in
four reasons. One, he hypothesized that the continents were once a giant
continent. Two, he observed that there are fossils found of the same kind in
the different locations. Three, he found that the edge of opposing continents
somehow fits if they are combined, almost like a puzzle. And four, there are
glacial scars that are left behind by a larger glacial continent. His greatest
weakness of Alfred Wegeners’ continental drift theory was he could not explain
what kind of force that caused this continents to move far from each other.