Corrected sentences:
The black lemur is rare. Without our help, it might disappear forever.
Or as one sentence:
The black lemur is rare, and without our help, it might disappear forever.
Easy explanation for a 6-year-old:
- Start with a big letter: "The" must be capitalized at the beginning.
- Sometimes it's easier to make two short sentences: "The black lemur is rare." and "Without our help, it might disappear forever."
- If you join the two thoughts into one sentence, put a comma before "and": "rare, and..."
- Put a little pause (a comma) after "Without our help" because it comes at the start of the sentence.
- "Rare" means there are not many left. "Disappear forever" means they could be gone and never come back, so we should try to help them.