<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 the answer is a) the scientific method involves developing and testing questions
Soil erosion is defined as the wearing away of topsoil. Topsoil is the top layer of soil and is the most fertile because it contains the most organic, nutrient-rich materials. Therefore, this is the layer that farmers want to protect for growing their crops and ranchers want to protect for growing grasses for their cattle to graze on.
