A. fact B. continuously C. ignore D. when E. much F. shows G. prevented H. plays I. limited J. unconsciously K. data L. unpredictable M. tools N. attend O. because In recent decades, scientists have become increasingly aware of the part the observer 1 in the scientific process. In the first place, the observer can work only with his experiences, and these are 2 by his senses and the instruments he uses to extend his senses. Ultraviolet light, electromagnetic fields, and atomic particles, for example, became known to us only as we devised 3 with which we could observe their effects. Consequently, our picture of the real world is always incomplete. Secondly, the observer is highly selective in choosing his 4. Life is a narrative of ever new and often 5 events. At any given moment, an individual is bombarded with sense experiences and can, if he desires, expose himself to more. But he is really interested in or concerned with only a few of these. Other experiences are consciously or 6 screened out as irrelevant to the task at hand. For example, as we read a book, we are often surrounded by sounds and activities that we 7, but by turning our attention to them we become conscious of their presence. What a scientist discovers depends, to a great extent, on what he is looking for— on the questions he is asking. Thus, academic disciplines differ in their study of human beings in large part 8 they ask different questions. Human beings live, so to speak, in a house with only a few windows of tinted and curved glass, through which we see the outside world. The glass colors and distorts our observations, and its effects can be determined only with 9 difficulty. Scientists are increasingly aware of the 10 that they work with sense data, not with the world itself.