Final answer:
Hormones in the endocrine system play a large role in motivation for sexual activity.
Step-by-step explanation:
When we are motivated to engage in sexual activity, hormones in the endocrine system play a large role in motivation. The endocrine system is responsible for the production and release of hormones, which are chemical messengers that regulate various bodily processes including sexual behavior. In the context of sexual motivation, hormones such as testosterone and estrogen play important roles in regulating desire, arousal, and reproductive functions.