New to NoSQL and a little confused with creating collections - database

Question

Im a student just starting out on NoSQL and its just not clicking with me. im a little confused on a few points.
Any help would be greatly appreciated
1.Can documents belong to multiple collections?
2.Have I the correct syntax here for creating the Collection?
The pic is the collection er and a is just a snippet of the full er.
db.Animal.insert ( {
“animal_ID” : “XXXXXXX “,
“common_name” : “Red Squirrel”,
“IUCN” : “Least Concern (declining)”,
“photo” : “qs451xkx6qf4j”,
“extinct” : {
“when” : “null “,
“reason” : “null”
},
“invasive” : {
“threat_level” : “null”,
“threat” : “null”,
“how_to_help” : “null”
},
“native” : {
“endangerment” : “population declining“,
“how_to_help” : “providing a little extra food, planting some red squirrel-friendly shrubs and reporting any red or grey squirrel activity”
},
“Fact_sheet” : “{
“fact_id” : “ “,
“animal_id” : “ XXXXXXX “,
“order” : “ Rodentia “,
“family” : “Sciuridae “ ,
“species” : “Sciurus vulgaris “ ,
“size” : “body length 19 to 23 cm, tail length 15 to 20 cm “ ,
“weight” : “250 to 340 g “ ,
“lifespan” : “3 years , 7 to 10 in captivity “ ,
“extra” : “In Norse mythology, Ratatoskr is a red squirrel who runs up and down with messages in the world tree, Yggdrasil, and spreads gossip “ ,
“habitat” : { [
“name” : “woodland “,
“description” : “a low-density forest forming open habitats with plenty of sunlight and limited shade “
]
});

Answer 1

Can documents belong to multiple collections?
In MongoDB, no. In other databases, I don't know.
2.Have I the correct syntax here for creating the Collection?
To create a collection you would use https://docs.mongodb.com/manual/reference/method/db.createCollection/. This call also permits you to pass various collection options.
You are inserting a document. In MongoDB when a document is inserted, if the destination collection doesn't exist, it is created automatically by the server.