Answer:
Cardiovascular is the correct option
Vestigial structures are considered evidence since scientists believe they are structures that were once used by a species ancestors but are no longer needed. They do not impair the organisms in any way, so there is no need for evolution to get rid of them. Vestigial structures are anatomical features that no longer seems to have a function or purpose in the current form of an organism of the given species. Examples are wisdom teeth, the muscles of the ear, the appendix, the tail bone among others in human.
In animals, the circulatory system performs a similar function because it transports vital nutrients around the body of the animal, just like how xylem and phloem transport water, minerals, and sugar to different parts of the plant.
After Santiago slaughters the immense marlin in The Old Man and the Sea, by Ernest Hemingway, he lashes it to the side of his watercraft. The fish is eighteen feet long, longer than the watercraft, and Santiago knows he won't make great time going home in light of the additional weight and clumsiness of the fish. He doesn't get much of anywhere before the principal sharks strike the fish.
It is the b. food chain and begins with plant, then animals that eat plants, and finally animals that eat other animals.