Answer: A) The 'lub' sound is caused as the atrioventricular valves close.
Explanation:
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When contracted the Right Atrium pumps deoxygenated blood into the Right Ventricle below via the Tricuspid Valve.
The answer would be c. plant trees around farmland. This is because the trees will protect the soil from being affected by the wind.
Answer: Answer is B a hot spot
Explanation: