Ascientist is trying to determine whether the use of hair dye contributes to brain cancer. for his study, he compares the medical records of subjects that have been diagnosed with brain cancer to the records of healthy subjects. what is the most significant weakness in this type of study? a. the test groups must be unusually large to generate significant data. b. the relationship between the hair dye and the cancer is difficult to determine. c. this type of study is expensive and the data is difficult to analyze. d. this type of study must rely on medical records, which are often inaccurate or incomplete.

Liquefaction was one reason the kobe wharfs were destroyed and other areas nearby. what is liquefaction? a. it is when conditions in the soil send the seismic wave out to the mountains and bounce back b. it is when conditions in the soil change to vigorous p-wave shaking when the surface waves pass by c. it referes to the fact that when an earthquake occurs wet and soft soil will vibrate more vigorously then solid rocky soil strangely in kobe some streets had very bad damage but the next street over had far less damage. what caused this? a. the waves passed through the city hit the mountains and returned back to the city. at some points the incoming and outgoing waves amplified their strength b. the mountains also had a quake and sent waves into the city c. waves hit the moutains and took longer to return

Which experiment would most likely contain experimental bias

What sre the effects of hemolytic disease of a newborn