<span>The correct answer is b. Radon. Oxygen, Hyrdrogen, and Boron, are not radioactivel ike Radon and it regenerates quickly meaning that even though it has a short half-life period, it stays for a long time once released. It also has no taste so it's difficult to notice without proper gear because you can't feel it.</span>
Solid! The molecules in solid matter are arranged closely together and packed quite tightly to maintain a regular shape. Hope this helps!
Answer:
The answer is "3.81041978"
Explanation:


In 1860 





Answer:
C
Explanation:
75 mile shallow flat area just off coastlines
Answer:
Both are chemical changes.
Explanation:
They are chemical changes because when when you melt the sugar to make caramel a new substance is formed. The same with cookies. You don't start out with cookies, you start out with dough. And then when you cook the dough a new substance is formed which is the cookies.