Growth of chest hair, deepening of the voice, and muscle growth are secondary sex characteristics. Which structure or structures produce substances most likely to affect the development of these traits?

The testes produce testosterone, a hormone that promotes male secondary sex characteristics such as chest hair, a deeper voice, and increased muscle growth. The ovaries produce hormones associated with female reproductive development, while the prostate gland and vulva do not produce the hormones responsible for these traits. Therefore, the correct choice is the testes.

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