Data quality issues involved in observational science'

Many sciences rely on observation instead of (or in addition to) designed experiments. Compare the data quality issues involved in observational science with those of experimental science and data mining.For the answer:A) List 2 drawbacks involved in observational science. Explain each drawback with 1 sentence.B) List 2 drawbacks involved in experimental science. Explain each drawback with 1 sentence.C) Explain in less than 4 sentences why would you prefer one approach over the other (observational and experimental approach).