The answer is C. El Niño would cause changes in the genetic makeup of organisms.
The correct answer is option ''The stethoscope was invented because the physician did not want to put his head on women's chests to listen to their heart and lungs''.
In this case, the problem was that the physician's had a problem in listening the heart beats and the lung sound of the woman. To overcome this problem, the stethoscope was invented to listen the heart beat and the lung sound from distance, without keeping head on women's chest.
Natural variation provided the phenotypes that natural selection then acted on, over time causing evolution
Answer:
A. looking for ways to improve the quality of water
