Respiratory system is refers to as the organs which are involved in breathing such as nose, throat, larynx, trachea, bronchi, and lungs. It is also known as respiratory tract.
The circulatory system is refer to as which contains the heart and the blood vessels and blood moves throughout the body in vessels. This circulatory system helps tissues to get enough oxygen and nutrients, and it helps them get rid of waste products.
<h3>
</h3><h3>
What is breathing?</h3>
When person inhale (breathe in), air enters in the lungs, and oxygen from atmosphere moves to body blood. At the same time, carbon dioxide, a waste gas, moves from blood to the lungs and is exhaled (breathed out).
Breathing process is known as gas exchange which is is essential to life.
For more information regarding breathing, visit:
brainly.com/question/15001725
#SPJ
I think it is A but not 100% sure. Think of an enzyme like a key unlock the lock is the protein. And to activate getting inside your car or house you have to fit the key into the lock.
In general, the term organelle is used for the small structures within a cell.
