According to the slides, all hormones travel only through the bloodstream.

This statement is **false**. The slides say that most hormones enter the blood, but some chemical signals are released into the environment as **ectohormones or pheromones**. The word *most* is important: it does not mean *all*.\n\n**Key takeaway:** Blood is a common route for hormones, but environmental signaling is also described.\n\n**Glossary:** **Pheromone**: A chemical signal carrying information between members of the same species; **ectohormone**: An environmental chemical messenger, as described in the slides.