How can different file extensions (.php, .php3, .php4) affect the parsing of PHP scripts in Apache?

Different file extensions can affect the parsing of PHP scripts in Apache because Apache may not recognize certain extensions as PHP files by default. To solve this issue, you can use the AddType directive in your Apache configuration to explicitly associate the desired file extensions with the PHP handler. ```apache AddType application/x-httpd-php .php .php3 .php4 ```