Scientists collected samples of each group of flies. They placed some of the flies, together, in flasks with both apples and hawthorn fruit. Other flasks contained either apple-eating flies or Hawthorne-eating flies. Only the flies in the single fruit flasks mated and produced offspring. To confirm their results, the scientists isolated flies from each group and put one of each into a flask with food. Eventually, the flies died without mating. What conclusions apply to this situation? All BUT ONE could apply.

there are so many examples for that in different areas, like biology experiment carried out in our lab recently.

here's one link:

the scientific method.

you know that this symptom is misleading and quite often is related to: heart attack

a heart attack is a condition that occurs when the blood flow that transports oxygen to the heart muscle is damaged or cut off completely. the coronary arteries that supply the heart muscle with blood flow can be blocked by the accumulation of plaque. also, when the plaque within the heart artery breaks, it creates blood clot that can also hinder the blood flow. men that are over 45years of age and women that are over 55years of age are at risk of having a heart attack. the symptoms of a heart attack include chest discomfort, chest pain, coughing, and shortness of breath.