Verse 4

केचित्स्ववासनातन्तुबद्धाः कर्मफलोदिताः ।तिर्यक्त्वात्स्थावरतनुं यान्ति तिर्यक्तनुं ततः

In plain words

Some, bound by the threads of their own vāsanā, raised up by the fruits of karma, go from animal existence to a stationary [plant] body, and from there to an animal body.