The correct answer is C. opened.
Science has opened up the mysteries of nature to man. This means that science has made it possible for us to understand the natural world in a way that was not possible before. Science has revealed the secrets of the universe, from the smallest particles to the largest galaxies. It has also given us insights into the workings of the human body and mind.
The other options are incorrect because they do not accurately reflect the meaning of the sentence. Option A, released, suggests that science has somehow freed the mysteries of nature from captivity. Option B, disclosed, suggests that science has made the mysteries of nature known to us. Option D, cleared, suggests that science has removed any obstacles that were preventing us from understanding the mysteries of nature.
In conclusion, the correct answer is C. opened. Science has opened up the mysteries of nature to man, making it possible for us to understand the natural world in a way that was not possible before.
