1. Fluctuations of aggregate economic activity. 2.Cycles Expansion/Boom and Contraction/Recession. Peak and Trough: They are the turning Points of the business cycle. 3. Comovements of many macro variables over the business cycle.
Section 5: Using external media: CDs, DVDs and removable USB storage devices. â¢ dvd-r:until about 2005 the most common and portable format; cannot be erased or reused. â¢ dvd-rw:are-writable version of-rformat, similar to cdrw format CD discs.
A CD-ROM /ËsiËËdiËËrÉm/ is a pre-pressed optical compact disc which contains data. The name is an acronym which stands for  Compact Disc Read-Only Memory . Computers can read CD-ROMs, but cannot write to CD-ROMs which are not writable or erasable.