The first statement is not entirely accurate. The symbol table is accessed during different phases of a compiler, including lexical analysis, syntax analysis, semantic analysis, and code generation. It is used to store information about identifiers, such as variable names and their attributes, throughout the compilation process.
Ⅱ. The second statement is true. Compilers for programming languages that support recursion typically need heap storage for dynamic memory allocation during the run-time environment. Recursive function calls create a stack of activation records, and heap memory is often used for dynamic memory requirements.
Ⅲ. The third statement is not true. Errors violating the condition "any variable must be declared before its use" are detected during semantic analysis, not syntax analysis. Syntax analysis primarily focuses on the grammatical structure of the program, while semantic analysis checks for meaningfulness and correctness of the program, including variable declarations and usage.