I believe the answer is 1 unable to be conqured
The answer would be “energy”.
The sentence says that Caseyis a “bundle of energy”, meaning she is mostly very energetic and moves a lot. However, something happened to make her feel the opposite way (because of the high fever), or lethargic.
The antonym of “lethargic” (which means very sluggish) is “energy”.
Think about the physical message you're sending. ...
Be positive and energetic. ...
Use numbers whenever possible. ...
Be specific about your accomplishments. ...
Tailor your pitch to the situation and the person. ...
Don't ramble.