The order of flow of oxygen within the human body may be described simply. Oxygen first is inhaled through the nasal cavity and then passes through the trachea, through the bronchi and into the lungs. In the lungs, the oxygen is passed into the blood stream through the alveoli and then is carried to the heart. The heart pumps this oxygenated blood throughout the body, primarily to organs and muscle cells, where it is consumed in respiration and is converted to carbon dioxide and excreted.
Answer:
Aristotle first wrote about the practice of animal testing in ancient
Greece during the third century BC.
Explanation:
You see first the light wave because light travels faster than sound. Hope this helps
<h2>
What are leukocytes?</h2>
Leukocytes are colorless cells that circulate in the blood and belongs to the body's immune system and helps the body fight infections and other diseases.
<h2>
What is their function?</h2>
Leukocytes are responsible for fighting other diseases and protecting your body from infections. Since they are part of the immune system, leukocytes circulate your blood and help cure injuries or illness.
Animals have many advantages. But plants can make food anywhere there is sunlight/ultraviolet rays. So no need to hunt unless you're a Venus Flytrap. So plant cells can sustain themselves easier to a degree. As with many things in biology, it all comes down the the circumstances.
