For each of the following questions, arrange the sentences A, B, C, and D between sentences 1 and 6 to form a logical sequence with sentence 1 and sentence 6 as the starting sentence and the concluding sentence respectively.
(1) Man has existed for about a million years.
A- Science, as a dominant factor in determining the beliefs of educated human beings, has existed for about 300 years; as a source of economic technique for about 150 years.
B- When we consider how recently it has risen to power, we find ourselves forced to believe that we are at the very beginning of its contribution in transforming human life.
C- In this brief period, it has proved itself as an incredibly powerful revolutionary force.
D- He has possessed writing for about 6000 years, and agriculture for perhaps just a little longer.
(6) What its future effects will be is a matter of conjecture, but possibly a study of its effects up till now may make the conjecture a little more meaningful.