Почему уменьшается длина рельса при его охлаждения? А. Уменьшается расстояние между молекулами. Б. Уменьшается объём молекул. В. Увеличивается сила притяжения. 
Заранее спасибо. 

найдите наименьшее общее кратное чисел  54 и120 .

найдите наибольший общий делитель чисел 2340 и 8910

какое значение выражения 70-4=(60+10)-4=60+(10-4)=

Определите форму глагола – сказуемого (залог, время).
Some blind and partially sighted people use computer-based technology to gain access to printed information. 2. In 1997, a new technology emerged that brought digital sound and video into homes over the world. 3. Since 2006 another revolution with the introduction of Blu-ray Discs has taken place. 4. Users will be able to connect to the Internet via Wi-Fi. 5. Minicomputers are becoming less popular as microcomputers improve. 6. We have been solving the problem since 1993. 7. Up to this point we have been discussing information retrieval in general terms. 8. Two keys are usually employed, one to encode and the other to decode the information.  9. The separate elements of the building have been manufactured at different factories. 10. Computer Security techniques are being developed to protect single computers from accidental or intentional invasion of data by unauthorized individuals. 11. Science is the means by which the hole of our civilization is rapidly being transformed. 12. The new device will have been tested before the chief engineer comes.
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