A proper noun is usually understood as a noun that is capitalized. In order to be a proper noun, like any other noun, the word must be a person, place, thing, or idea.
Proper nouns, no matter where they are in the sentence, have their first letter capitalized.
When at the beginning of a sentence, it does not matter whether or not the noun is proper: it is capitalized anyway. This is exactly why you have to learn exactly which words are proper nouns by memorization.
The sirens would show themselves as beautiful mermaids, and they would sing of the sailors' greatest desires and offer them their greatest desires.
Answer:
To inform the reader about some basic facts regarding the planet Mars
I don't think he would neglect his children, or allow elders to make all the decisions, I believe that he would encourage his children to play on his own. I would go with he encourages children to play on their own.
