First, I see no italics. Second, your sentence looks like it has no errors.
<span>A phoneme is a single "unit" of sound. a phoneme means that there is a several words with a diffrent meaning or spelling that sounds the same when spoken. A good example would be the word "not" but also sounds like "caught" but then theres also another words like "thought" they carry the same sound when spoken. but spelled diffrent when said out loud</span>
Answer:
The lungs are separated by the mediastinum. - c.
If you were out of breath from just walking, talk to your doctor. Something could be wrong. If you reached your target heart rate, you could know that by taking your heartbeat after or during walking