Answer:
a,c,d
Step-by-step explanation:
Crossing over occcur when genetic material is exchanged between homologous chromosome this leads to formation of new genes that creates diversity.
homologous chromosome assort imdependently i.e seperate from each other leading to the formation of an entirely new gene that creates diversity.
Genetic recombination when gene recombines together to produce a unique type. It occurs between different species.