The immune system. It produces antibodies which fight the bacteria or virus that caused the infection
Explanation:
Hence, the correct answer is 'Nuclear membrane'.

Answer:
C. Prohase 1
Explanation:
It is during prophase 1 of meiosis that crossing over occurs before tetrads or homologues pair of chromosomes are alligned across the equator of metaphase 1. In Meiosis 11, only the sister chromatics will be left or remain and the homologues pair of chromosomes would be moved to separate cells.