Question

cyanocitta garrulus is a blue bird with an orange - brown back. the offspring of this bird have an effective defense mechanism. the young birds vomit and cover themselves in a foul - smelling orange liquid when they sense a threat by predators. which two systems alert the young bird to the danger and help produce the vomit it uses as defense?

• excretory and reproductive
• nervous and digestive
• immune and respiratory
• integumentary and muscular

Explanation:

首先，鸟类感知捕食者威胁需要神经系统来接收、传递和处理外界的危险信号；而产生呕吐的防御行为则依赖消化系统来分泌、产生并排出用于防御的呕吐物。其他选项中的系统均不具备感知危险并产生该防御分泌物的功能。

Answer:

B. nervous and digestive