Final answer:
Yes, all proper nouns start with a capital letter.
Step-by-step explanation:
Yes, all proper nouns start with a capital letter.
Proper nouns are specific names of people, places, things, or animals. They are always capitalized to distinguish them from common nouns. For example, 'John' is a proper noun because it refers to a specific person.
Other examples of proper nouns include 'London' (a specific place), 'Eiffel Tower' (a specific thing), and 'Lion' (a specific animal).
Learn more about Capitalization rules for proper nouns