The answer is the first one A
Atoms are the smallest building blocks of elements having the same chemical and physical properties of that specific element. Atoms combine together with the help of electrons, to form a little more complex entity like the molecules, crystals, liquids etc. Some molecules combine together to form a more complex entity like the DNA which is the most complex molecule. The whole universe is made out of these simple building blocks, including the human body.
Spirillum, genus of spiral-shaped bacteria of the family Spirillaceae, aquatic except for one species that causes a type of rat-bite fever in man. The termspirillum<span> is used generally for any of the corkscrew-like species. sounds scary really isnt but it so cooool</span>
Answer;
A. Blood
Explanation;
The main organs of the Circulatory system are the heart, the brain, the lungs. There are other key things like arteries, veins, and capillaries but they are not organs.
The major tissues in the circulatory system are the epithelial, muscle, nervous, and connective tissues.
Blood is the main connective tissue in the circulatory system, but it's a liquid connective tissue. Blood tissue is in the same family as bone and cartilage, but instead it has a liquid medium that holds it together.
