It's called a conduit.
Hope this helped!
Answer:ryanodine receptor, or RYR) in the sarcoplasmic reticulum (SR), causes opening of the RYR. In cardiac muscle, opening of the L-type calcium channel permits influx of calcium into the cell
Explanation:
The correct answer is D.) The sun
The sun’s heat causes liquids to evaporate into water vapor, which rises and forms clouds. The whole water cycle repeats itself again because of the sun.
It's called a <span>trephination!!
- Good luck</span>
