Answer:
The answer may be coincidence
Swimming because I love water and I know how to swim .
<span>The upper chamber is called an atrium (or auricle), and the lower chamber is called a ventricle. The two atria act as receiving chambers for blood entering the heart; the more muscular ventricles pump the blood out of the heart.</span>
The epithelial cells tend to be cuboidal in shape when they are inactive, but more columnar when they are actively secreting hormones. The epithelial cells accumulate iodine from the blood and use this element in the synthesis of thyroglobulin, a large glycoprotein which forms the colloid.
hope this helps