What is a System software that serve as a platform/supports other programs/software in a computer system

Jackson, who works in the finance department of a company, is holding a seminar for other employees on how to file taxes. only three employees sign up to attend the seminar. which device can he use to share his presentation with a group of three employees?

Which of the following "invisible" marks represents an inserted tab?

Which of these is not a type of socket? aga (alternating grid array) pga (pin grid array) spga (staggered pin grid array) lga (land grid array)