External criticism is very important when it comes to analyzing data, because as a researcher it is possible to get too "close" to the data, in that one can stop being objective and start looking for ways to match the data to the desired results.
An organ is a structure composed of two to four types of tissues working to perform functions that are beyond the scope of an individual tissue type. A set of related organs working cooperatively toward the performance of even more complex functions constitutes an organ system.
I am pretty sure the answer is B) sedimentation but i could be wrong. i haven't don't this subject in a year. lol