Identify the scientist who discovered anesthetic, which allows people to withstand pain and be unconscious during surgery.

A. Crawford W. Long

B. Sigmund Freud

C. Ivan Pavlov

D. Louis Pasteur

Crawford W. Long (1815 - 1878) was an American surgeon, best known for his first use of inhaled sulfuric acid as an anesthetic. He published his findings in 1849. Sigmund Freud was an Austrian neurologist and the founder of psychoanalysis. Ivan Pavlov was a Russian physiologist, known for his work in classical conditioning. Luis Pasteur was a French biologist who discovered the principles of vaccination and pasteurization. Answer: A. Crawford W. Long

The answer is Ivan Pavlov