sexual reproduction is a kind of reproduction & the reproductive system is used for sexual reproduction ->  the reproductive system is used for reproduction  producing offspring ensures the continuation of a species & reproduction produces offspring ->  reproduction ensures the continuation of a plant or animal species  the reproductive system is used for reproduction & reproduction ensures the continuation of a plant or animal species ->  the reproductive system is used for continuing the species  the reproductive system is used for continuing the species & if something is used for a performing a process, then performing that process is a function of that something -> a function of the reproductive system is continuing the species