Answer:
Behavioral adaptation
Step-by-step explanation:
There are mainly three types of adaptation seen in an organism that are structural, physiological, and behavioral adaptation. Structural adaptation is mainly physical adaptation in some structures of the organism like teeth are different in different organisms according to the food they eat.
Physiological adaptation is the adaption occurs due to change in the external stimuli in physiology of an organism. Behavioral adaptation is the adaptation that helps organism to survive in their environment. Their behavior can be learned or present from birth.
Spittlebugs release foam to hide in branches is an example of behavioral adaptation because this is the instinct of spittlebugs which protects them from predators and helps it to survive in its habitat.
So it is in the behavior of spittlebugs to release foam when it feels a threat and when it does not feel threat it does not form the foam.