Answer the following question given this paragraph: 

The gonads are glands that secrete sex hormones. Male gonads are called testes. They secrete the male sex hormone testosterone. The female gonads are called ovaries. They secrete the female sex hormone estrogen. Sex hormones stimulate the changes of puberty. They also control the production of sperm or eggs by the gonads.


Q: What stimulates the changes of pubery?

 Choices:

- sex education

- mutation

- parenting

- sex hormones

A:
sex hormones
