I feel the answer is cell membrane .
The cell membrane is a semipermeable protection and covering for the cell.
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Answer:
the answer may be optionA..
Answer: Respiration in Animals.
Explanation:
This is a body systems which involves the intake of oxygen, and the release of carbon dioxide ,(breathing),for the breakdown of digested food substances for example (glucose), to generate energy.
Most organisms make s use of oxygen for survival they are aerobes, while some organisms thrived in absence of Oxygen; these are anaerobes.The
Ions are formed when an atom gains or lose electron during a chemical reaction.
<h3>How ions are formed?</h3>
Ions are formed by the addition of electrons or the removal of electrons from an atoms or molecules by the combination of ions with other particles. Ions formation occurs during covalent bond formation and ionic bond formation between different molecules. Those substances that gains electron bears positive ion while on the other hand, those elements that lose electron forms negative ion or charge on the atom.
So we can conclude that ions are formed when an atom gains or lose electron during a chemical reaction.
Learn more about ions here: brainly.com/question/2687188
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