Which is NOT a method used to extract stem cells? retrieval from blood donations
retrieval from embryos
retrieval from umbilical cords
retrieval from bone marrow

silty loam

hope this

the principles and empirical processes of discovery and demonstration considered characteristic of or necessary for scientific investigation, generally involving the observation of phenomena, the formulation of a hypothesis concerning the phenomena, experimentation to test the hypothesis, and development of a conclusion that confirms, rejects, or modifies the hypothesis.

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