No. 081
　　As rock interfaces are crossed, the elastic characteristics encountered generally change abruptly, which causes part of the energy to be reflected back to the surface, where it is recorded by seismic instruments.

　　No. 082
　　While the new doctrine seems almost certainly correct, the one papyrus fragment raises the specter that another may be unearthed, showing, for instance, that it was a posthumous production of the Danaid tetralogy which bested Sophocles, and throwing the date once more into utter confusion.

　　No. 083
　　The methods that a community devises to perpetuate itself come into being to preserve aspects of the cultural legacy that that community perceives as essential.

　　No. 084
　　Traditionally, pollination by wind has been viewed as a reproductive process marked by random events in which the vagaries of the wind are compensated for by the generation of vast quantities of pollen, so that the ultimate production of new seeds is assured at the expense of producing much more pollen than is actually used.

　　No. 085
　　Because the potential hazards pollen grains are subject to as they are transported over long distances are enormous, wind pollinated plants have, in the view above, compensated for the ensuing loss of pollen through happenstance by virtue of producing an amount of pollen that is one to three orders of magnitude greater than the amount produced by species pollinated by insects.

　　No. 086
　　For example, the spiral arrangement of scale-bract complexes on ovule-bearing pine cones, where the female reproductive organs of conifers are located, is important to the production of airflow patterns that spiral over the cone’s surfaces, thereby passing airborne pollen from one scale to the next.

　　No. 087
　　Friedrich Engels, however, predicted that women would be liberated from the “social, legal, and economic subordination” of the family by technological developments that made possible the recruitment of “the whole female sex into public industry”.

　　No. 088
　　It was not the change in office technology, but rather the separation of secretarial work, previously seen as an apprenticeship for beginning managers, from administrative work that in the 1880s created a new class of “dead-end” jobs, thenceforth considered “women’s work”.

　　No. 089
　　The increase in the numbers of married women employed outside the home in the twentieth century had less to do with the mechanization of housework and an increase in leisure time for these women that it did with their own economic necessity and with high marriage rates that shrank the available pool of single women workers, previously, in many cases, the only women employers would hire.

　　No. 090
　　For one thing, no population can be driven entirely by density-independent factors all the time.