height threaten the existance of other people & threatening the existence of an animal has a negative impact on that animal ->  predators have a negative impact on an animal's survival  predators have a negative impact on an animal's survival & avoiding something with a yes oven has a uncertain motion -> avoiding predators has a positive impact on an organism 's survival avoiding predators has a positive impact on an organism 's survival  avoiding predators has a positive impact on an organism 's survival & limit can thwart people avoid brushing -> organisms will use defenses as a reseponse to predators organisms will use defenses as a reseponse to predators  display are a mean of attack holding & quills are part of a porcupine -> quills are part of a porcupine used for defense quills are part of a porcupine used for defense  organisms will use defenses as a reseponse to predators & guanine are whole of a extract used for attack -> a porcupine will use quills as a response to predators