What is blockchain? how it works? i heard bitcoin uses it.

"gps interaction and cognitive process" respond to the following: imagine that you have been asked to design a gps product that will have voice recognition and bluetooth capability. discuss and conceptualize a user interaction model. predict two (2) problems that may arise in gps products with voice recognition and bluetooth capability. recommend solutions for each of these issues. attention is one of the six cognition processes. when attention is applied to a design, the goal is to make it easier for the end user to quickly locate where he / she should type information on the computer or mobile device screen. compare and contrast how the google search engine and the microsoft bing search engine employ the attention cognition process. provide your opinion as to which search engine better employs the attention cognition process and explain why.