Which enzyme is responsible for crossing over during meiosis?
Recombinase facilitates crossing over during the pachytene stage of prophase I in meiosis. This follows from NCERT principle where the relation explains the outcome clearly for students in simple steps.
Ref: NCERT Biology Textbook for Class XI and XII (Botany section), Chapter: Morphology and Anatomy of Flowering Plants, Topic: Plant structure and tissue systems.