In distributed dos attacks, the attacker sends messages directly to bots the intended victim of the dos attack backdoors dos clients dos servers

The word DoS refers to the Disk Operating System. In the case given above, if it happens that there is a distributed DoS attack, the attacker then sends messages directly to the BOTS. Bots refer to internet or web robots. Hope this answer helps. The answer is the first option.

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Well, this code would box the whole body of an html document. by using the relative value for position, you are telling it to position relative to its normal position, which the top left corner is at (0,0). by using left: 50px, you are telling the box to set the left margin  edge to 50px and by using top: 50px, you are telling it to set the top margin edge to 50px. by doing this shifting, the top left corner of the box, which is at (0,0) would be positioned at (50,50)