What is rough endoplasmic reticulum

The rough endoplasmic reticulum can be found in both an animal cell and a plant cell. It is located next to the nucleus in a cell. It's function is to produce and modify proteins. It is called the 'rough' endoplasmic reticulum because it contains ribosomes on its outside layer

The speed of  sound:   sound travels  at different speeds depending on what it istraveling through. of the three mediums (gas, liquid, and solid)  sound waves travel the slowest through  gases, faster  through  liquids, and fastest  through  solids.