Final answer:
True, adult heartworms inhabit both the heart's right ventricle and the pulmonary arteries in dogs, and can cause serious health issues if not prevented. The correct option is A.
Step-by-step explanation:
The statement that adult heartworms live in the dog's heart as well as in the pulmonary arteries is true. Adult heartworms, which are nematodes (roundworms) known as Dirofilaria, do indeed reside in the right ventricle of the heart in dogs, and they can also be found in the pulmonary arteries.
The worms are capable of producing offspring, known as microfilariae, which can invade the host's bloodstream. It's critical for dog owners to be aware of heartworm infection risks and ensure their pets receive regular preventative treatments to avoid serious health complications, such as coughing, vomiting, trouble breathing, and even heart failure in advanced cases.