Question

In circulatory system, valves occur in:
A. Heart and blood vessels of both vertebrates and invertebrates, as well as vertebrate lymphatics.
B. Both vertebrate and invertebrate hearts.
C. Vertebrate heart only.
D. Both vertebrate and invertebrate hearts and their blood vessels Hard.

Answer 1

Hint Invertebrate animals like insects, arthropods, and most mollusks have an open cardiovascular system, blood bathes the interior organs directly. When the hearts relax, they draw hemolymph through pores, which are equipped with valves that close when the guts contract.

Complete answer:
Single-celled organisms use their cell surface as some extent of exchange with the surface environment. Multicellular organisms have developed transport and circulatory systems to deliver oxygen and food to cells and take away CO2 and metabolic wastes. Sponges are the only animals, yet even they need a transport system.
Seawater is the medium of transport and is propelled in and out of the sponge by ciliary action. Simple animals, like the hydra and planaria, lack specialized organs like hearts and blood vessels, instead of using their skin as an exchange point for materials. This, however, limits the dimensions an animal can attain. To become larger, they have specialized organs and organ systems.
Almost all multicellular organisms need a cardiovascular system to move oxygen and nutrients through the body. Evolution has led to the existence of two sorts of circulatory systems namely:
Open circulatory system: primarily found in invertebrates. Here, the blood flows freely through cavities since there are not any vessels to conduct the blood.
Closed circulatory system: is found in vertebrates and a couple of invertebrates like earthworms. This technique has vessels that conduct blood throughout the body.

Hence the correct option is (A).

Note: Animals like annelids, some mollusks, and vertebrates have closed circulatory systems, the blood is confined within blood vessels. Chambered hearts with valves and comparatively thick muscular walls are less commonly found in invertebrates but occur in some mollusks, especially cephalopods.