The heart, lungs, blood vessels, and blood
<span>Mammals are advanced synapsids, animals distinguished by having extra openings in the skull behind the eyes; this opening gave the synapsids stronger jaw muscles and jaws (the jaw muscles were anchored to the skull opening) than previous animals.
Synapsids include the mammals, and their ancestors, the pelycosaurs, therapsids, and cynodonts. Pelycosaurs (like Dimetrodon and Edaphosaurus) were early synapsids, they were mammal-like reptiles. Later synapsids include the therapsids and the cynodonts (with multicusped post-canine teeth; they lived from the late Permian through the Triassic period).
The cynodonts led to the true mammals. Over time, the synapsid gait became more upright and tail length decreased</span>
Food chain- is a diagram that shows how food energy moves from one organism to another in an environment. It begins with the plant life and ends with animal life. Plants get eaten by animals and animals eat other animals.
<span>A substance that is made of atoms of more than one type bound together is called a <span><u>compound</u>.
</span>A compound is a</span><span> substance consisting of atoms or ions of two or more different elements in definite proportions joined by chemical bonds into a molecule. </span><span>
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Answer – 3. A weakened form of a virus
When getting a vaccination, the substance which is injected into the body is a weakened form of a virus. This weakened from of the virus has the ability to arouse the body’s defense mechanism without causing an infection.
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