A.THOROUGHLY B.ASTRONAUT C.COMPETE D.ATMOSPHEREREAD THE FOLLOWING PASS...

2:A.thoroughly B.astronaut C.compete D.atmosphereRead the following passage and mark the correct answer to each of the followingquestions.ssSSSShhh… IT'S A SECRET!Throughout history and in every civilisation, people have felt the need to communicate insecret. In war time, military secrets need to be transferred securely to commanders withoutbeing understood by the enemy. During revolutions, those plotting to overthrow theestablishment need to ensure their communications remain undisclosed. The history ofsecret communication is long and fascinating. World events have changed on manyoccasions because of secret messages - secrets that were kept and secrets that were not!There are two ways to communicate in secret - either you conceal the fact that you aresending a message at all, (‘steganography’) or you obscure the meaning of your messagerather than its actual existence ('cryptology'), steganography is very old. In 440 BC,theGreek ruler, Histiaeus, sent a message to a fellow plotter in a revolt by shaving off the hairof his most loyal slave, tattooing a message on his head, allowing the slave’s hair to growback, then sending him to deliver the message.The slave passed through enemy lines easilysince he seemed to be carrying no communication. Another very old form of steganographyis invisible ink. Inks made of simple organic materials such as milk orlemon juice, whichturn dark when held over a flame, were used as early as the first century AD for very seriouscommunications. During the Second World War, both sides raced to create new secret inksand to find developers for the enemy'sinks, although in the end this form of steganographybecame impractical due to the large amount of communications involved.Although steganography is a very clever way to communicate in secret, it does have anAchilles heel. If the messenger does not do a particularly good job concealing their messageand some one finds it, all its secrets will be immediately revealed. This weakness soon led tothe idea of hiding the actual meaning of messages, so that they could not be read, even ifthey were discovered. The result was the development of cryptology.Cryptology hides the meaning of messages by using codes. Codes are essentially secretlanguages. Julius Caesar invented one. He replaced every letter in a word by the letter threeplaces away from it in the alphabet. A was D, B was E, and soon. Later on, any code thatused a system of letter replacement such as this was referred to as a ‘Caesarcode’. Of course,it doesn’t take much brain power to figure out most of these codes! Today, code makersdevise practically unbreakable codes using highly sophisticated mathematics and computerpower.Are cryptology and steganography used now? Well, you may be surprised to learn thatsecret communication is apart of everyday life! For example, every time you use your creditcard to buy something from a company over the Internet, cryptology is employed. Verycomplicated codes turn your credit card number into a pile of gibberishthat only the retailercan decipher, not anyone else, steganography is also thriving in the digital world.Secret messages can easily be hidden in e-mail, audio and image files. This is because mostdigital documents contain useless areas of data, so some of their information can be alteredwithout obvious effect.This is of concern to governments as they fear that criminals may beconcealing messages in files sent over the Internet. One thing is certain - secretcommunication is still just as much a part of life today as it was millennia ago![Source:SPOTLIGHT 11, Student’s Book, Express Publishing, 2007]