What material replaced stone as the primary materials used to make tools and machines by humans

Which of the following physical laws can make the flow of water seem more realistic? a. motion b. gravity c. fluid dynamics d. thermodynamics

Auser is given read permission to a file stored on an ntfs-formatted volume. the file is then copied to a folder on the same ntfs-formatted volume where the user has been given full control permission for that folder. when the user logs on to the computer holding the file and accesses its new location via a drive letter, what is the user's effective permission to the file? a. read b. full control c. no access d. modify e. none of the above

Description: write function lastfirst() that takes one argument—a list of strings of the format "lastname, firstname" —and returns a list consisting of two lists: (a) a list of all the last names (b) a list of all the first names