In Modals^x, Colons^x, Plurals^x

Hello, this is my first post here, I like to know these words kilometer centimeter Are those words noun if they are standing alone ? if it's, what kind of noun it's, proper noun or abstract noun or etc ? After that, I want to indentify the part of speech of the following sentence by using the...

Hello, this is my first post here, I like to know these words kilometer centimeter Are those words noun if they are standing alone ? if it's, what kind of noun it's, proper noun or abstract noun or etc ? After that, I want to indentify the part of speech of the following setence by using the...