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Test 1 / 30


The desert landscape is often assumed to be uniform(FORM) – a barren, fearless wasteland of endless sand or rubble and blistering, blinding sun. Anything more than a cursory(CURSOR) glance, however, reveals a much more highly nuanced topography, whose very diversity(DIVERSE) is made all the more visible by its near nakedness(NAKED) , veiled as it is by only the thinnest cloak of vegetation.

Deserts are among the most eroded landscapes on earth, uniquely(UNIQUE) vulnerable to the action and interaction of three powerful natural agents: the heating effects of the sun, the scouring power of sand-laden wind, and, perhaps more surprisingly, the occasional onslaught of rushing water. Together, these natural forces carry out the process of mechanical(MECH) weathering by which rocks are physically riven into ever smaller particles(PART) . Wind and water also act as agents of transportation, carrying the debris that result from weathering to new sites. The topography – the surfaces, shapes, and relief(RELIEVE) of the land – that these natural forces create depends not only on climate but also on the nature of the raw material upon which they work.

Test 2 / 30


The twentieth century witnessed a momentous(MOMENT) change in the relationship between science and society. In World War I scientists were conscripted and died in the trenches. In World War II they were exempted as national treasures and committed to secrecy(SECRET), and they rallied behind their country’s war effort. The explanation of the change is not hard to find – governments came to believe that theoretical(THEORY) research can produce practical improvements in industry, agriculture, and medicine.

The belief was firmly reinforced(FORCE) by developments such as the discovery of antibiotics and the application(APPLY) of nuclear physics to the production of atomic weapons. Science became so identified with practical benefits that the dependence of technology on science is commonly(COMMON) assumed to be a timeless(TIME) relationship and a single enterprise. Science and technology, research and development these are assumed to be almost inseparable(SEPARATE) twins. These rank among the sacred phrases of our time. The belief in the coupling of science and technology is now petrified in the dictionary definition of technology as applied science.