For two languages l1 and l2, denote their concatenation l1l2 as the set of strings obtained by concatenating strings from each of the languages:

Explain briefly why you cannot expect to find a previous version of every file with which you work.

Which of the following is not a way in which trees benefit the environment? a. they remove a significant amount of carbon dioxide from the atmosphere. b. they remove a significant amount of oxygen from the atmosphere. c. their roots hold soil in place, reducing rates of erosion. d. they remove ozone and particulates from the atmosphere. select the best answer from the choices provided a b c d

Drag the tiles to the correct boxes to complete the pairs. match the errors with their definitions. #name #value #ref when a formula produces output that is too lengthy to fit in the spreadsheet cell arrowright when you enter an invalid cell reference in a formula arrowright when you type text in cells that accept numeric data arrowright when you type in a cell reference that doesn’t exist arrowright reset next