Answer:
Hello!
There are multiple ways to tell a line from anything else, (segment, ray ex.)
A line never truely ends, and it is ALWAYS straight.
If it's:
~ Not straight
~ Has dots at ends
Then it's not a line
If it doesn't end, and is straight, then chances are, it is a line.
Take a look at the chart I have attached for different types of lines.
I hope this helped you, and have a great day!!!