To help the nervous system and brain develop.
Answer:
Pulmonary circulation moves blood between the heart and the lungs. It transports deoxygenated blood to the lungs to absorb oxygen and release carbon dioxide. The oxygenated blood then flows back to the heart. Systemic circulation moves blood between the heart and the rest of the body.
Explanation:
The chance that a human child will be born male is 50%
Crystallization
This is a technique commonly done by chemists to purify compounds. During crystallization, an impure,solid compound is dissolved with a hot solvent. In the container the impurities and the needed compound move freely. When the solution cools down, the solvent can cannot hold all the solutes. Each solute will form a crystal. Therefore each crystal is made of only one molecule. Once it cools down if will be placed in a cold bath to complete the crystallization.
There are living organisms that do these processes alongside one another to sustain a balanced cycle.