<span>connect is the answer to your question. Transition words add clarity to writing. So "A"
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Answer:
I think no 2 is the answer
A simile can be found when using "like" or "as" between two things. Example: I'm as happy as a clown.
Your question would be a metaphor. Both things are being compared to a science expieriment, probably meaning that they need to have an outcome, but it isn't known for sure if it will be a good or bad outcome.
Things like this can be taken many ways, so if you think something else, I'm sure it would work as well.