Another gas that was used to fill balloons was hydrogen. The reason why hydrogen is not used today is because it use to cause many fires when it was used to fill balloons up.
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Option a) H-H is the correct answer
Answer:
Holmium can absorb neutrons, so it is used in nuclear reactors to keep a chain reaction under control. Its alloys are used in some magnets. Holmium has no known biological role, and is non-toxic. Holmium is found as a minor component of the minerals monazite and bastnaesite.
Explanation:
this is basically used in industries
Oil is referred to as a fossil fuel because it is derived from fossils.
Fossil fuels are the result of dinosaur remains being put under pressure for millions of years.
