To find out how they form
Answer:
They are very important The very last answer
Explanation:
Control rods are an important technology for maintaining the desired state of fission reactions within a nuclear reactor. They constitute a real-time control of the fission process, which is crucial for both keeping the fission chain reaction active and preventing it from accelerating beyond control.
It's most likely the third answer choice....
if you are looking for the definition it is: Various structures in different species having the same function but have evolved separately.
Examples: wings of an insect and birds used for flying.
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