From the options given below, select the one which best explains the expression:

"By fits and starts"

Irregular

The expression "by fits and starts" means irregular. It describes something that happens in a sporadic or intermittent way, with periods of activity followed by periods of inactivity.

The other options are not as accurate descriptions of the expression. Primitive means "relating to the earliest stage of development". Autonomous means "self-governing". Harmonious means "in agreement or accord".