Answer: C) Stealth virus Explanation:

Answer: C) Both A & B Explanation: Secondary storage therefore needed because it is non-volatile, meaning it retains its contents without the need for a power supply. It also has the large storage capacity needed to store the operating system and all the programs and files needed by a modern computer system.

Answer: A) RAM Explanation: Volatile memory is computer memory that requires power to maintain the stored information. It is a temporary memeory which cannot contain information permanently. Example :: RAM or Random Access Memory

Answer: A) DRAM Explanation: Memory refresh is the process of periodically reading information from an area of computer memory and immediately rewriting the read information to the same area without modification, for the purpose of preserving the information. Memory refresh is a background maintenance process required during the operation of semiconductor dynamic random-access memory (DRAM), the most widely used type of computer memory.