Define amino acids, polypeptides, and
proteins.

Hello! The answer to your question would be as followed:

Amino acids - a simple organic compound containing an amino and carboxyl

Polypeptides - a linear organic polymer consisting of a large number of amino-acid residues bonded together in a chain, forming part of (or the whole of) a protein molecule.

Proteins - Polymers of amino acids

advantage of using stem cells in medical research:

1.       it provides medical benefits in the fields of therapeutic cloning and regenerative medicine.

2. it provides great potential for discovering treatments and cures to a variety of diseases including parkinson disease, spinal cord injuries, diabetes, alzheimer’s disease and many more.

3. limbs and organ could be grown in lab from stem cells and then used in transplant or treat illness.

sound moves fastest in solids because the molecules are tightly packed and it allows sound to vibrate