Answer:
1. False. Mnemonics are typically used in assembly languages, not fourth-level languages.
2. False. The hexadecimal number system is based on 16 digits (0-9 and A-F), not 15.
3. True. Computers primarily work on machine language, which consists of binary instructions that can be directly executed by the computer's hardware.
4. False. An assembler is used to convert assembly language to machine language, not an interpreter.
5. True. The binary system is based on 0's and 1's, representing the two possible states of a digital circuit or computer memory.