Is the mark of punctuation that might indicate that more information is to come a period, a dash, an exclamation point or a hyphen?

It is not a period because periods indicate that no further discussion is possible or desirable.

Example:
- The dog is tired.

This is a statement, so it shows no indication that any further information is going to be given

It is not an exclamation point because they indicate an interjection or exclamation to show strong feelings. Exclamation points are kind of like periods, though they show stronger emotion.

Example:
- My daughter is getting married!

This is an exclamation. Just like a statement, no further information is suggested to be said.

Dashes and hyphens are very similar, but have different functions. Dashes have a space on either side of it, while hyphens are not separated by spaces. Also, dashes are longer than hyphens.

Though, as for their functions, hyphens are used to connect compound words and numbers. Dashes on the other hand are used to indicate that further knowledge is needed.

Hyphens are used with numbers between 21 and 99

Example of hyphens:
- Check-in
- two-year-old
- ninety-nine

Example of dashes:
- You may think she is a liar -- she isn't.
- They might come to our party -- you never know.