Which of the following is a male reproductive organ?

The testes are the male reproductive organs responsible for producing sperm and male hormones, primarily testosterone. They play a crucial role in male fertility; the production of sperm occurs within the seminiferous tubules of the testes. Additionally, the testosterone produced is vital for the development of male secondary sexual characteristics during puberty and for ongoing reproductive functions throughout adulthood.

The other options refer to female reproductive organs. The ovaries are responsible for producing eggs and female hormones. The fallopian tubes facilitate the transport of eggs from the ovaries to the uterus, where fertilization can occur. The uterus is an organ where a fertilized egg can implant and develop during pregnancy. Thus, all the other choices are related to female reproductive anatomy and functions.