Physical Responses
- All plant cells have a cellulose cell wall which is difficult to penetrate
- Leaves are covered with waxy cuticle which is difficult to penetrate
- Layers of dead cells surrounding stem which is difficult to penetrate such as bark
Chemical Responses
- Plants can release chemicals such as poisons and antibacterial
Mechanical Responses
- Sharp thorns
- Hairs which irritate mouth of animals
- Leaves that droop or curl to scare animals
- Mimicry