Answer:
The Cell.
Explanation:
Living organisms are composed of single or multiple cells. The cell is termed the building block of life. Single cell organisms are called unicellular while multiple cell organisms are called multicellular. A single cell organism is capable of performing all the basic functions of life like reproduction, respiration etc
<u>Answer:</u>
The Answer is <em><u>Option D. </u></em>
<em>Exchange of respiratory gases, oxygen and carbon dioxide take place in the alveoli of the lungs. Oxygen which is inhaled from the atmosphere diffuses through the walls of the alveoli and reaches to the adjacent capillaries into the red blood cells.</em>
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I believe blood vessels constrict
Answer:
1 evolution 2 natural selection.
Explanation: