Final answer:
In Python, strings can contain not only letters a-z and A-Z, but also numbers, special characters, and whitespace.
Step-by-step explanation:
False. In Python, strings can contain not only letters a-z and A-Z, but also numbers, special characters, and whitespace. This means that a string can consist of any combination of these characters. For example, a string can be 'Hello123!', which includes letters, numbers, and a special character.