Ants are very small insects what can substituie small

Instead of using the word "small", you can use words such as:

- miniature

- tiny

- little

summary - a brief statement or account of the main points of something.

main idea - the main idea is defined as the main point of a speech or piece of writing.

paragraph - a distinct section of a piece of writing, usually dealing with a single theme and indicated by a new line, indentation, or numbering.