John is a sheep rancher in montana who wants to discourage predators from going after his sheep. he placed sheep meat with a nausea-inducing chemical; after eating it just one or two times, coyotes and wolves still ran up to lambs, but instead of attacking, they retreated, hid, and vomited. they had developed a to sheep.

They had developed a conditioned taste aversion to sheep.

Conditioned taste aversion is a type of classical conditioning in which an animal learns to associate the taste of a particular food with subsequent illness due to the consumption of poisonous or toxic substances in the food. An animal can develop a taste aversion when ingesting a particular food is followed by vomiting, nausea or illness. This trains the body of the animal to avoid further ingestion of the particular poisonous food in the future.

amber has allowed scientists to study dna that has been preserved over millions of years.

the answer is "a.) well–developed vascular system."

explanation: