Which of the following terms refers to a collection of different types of software that share the goal of infiltrating a computer and making it do something? a- malware b- virus c- spyware d- trojan horse

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)

Lymphocytes must recognize antigen and respond to another signal generated by microbial infection to become activated.