How can the issue of missing semicolons in PHP code affect the execution and lead to errors like "parse error, unexpected"?

Missing semicolons in PHP code can lead to syntax errors like "parse error, unexpected" because PHP expects a semicolon to mark the end of a statement. To fix this issue, carefully review the code and ensure that each statement is properly terminated with a semicolon.

// Incorrect code with missing semicolons
$variable1 = "Hello"
$variable2 = "World"

// Corrected code with semicolons added
$variable1 = "Hello";
$variable2 = "World";