Answer:
Address at Rice University on the Nation’s Space Effort
by John F. Kennedy (excerpt)
September 12, 1962
Explanation:
Answer:
Lessen
Explanation:
Alleviate means to make (suffering, deficiency, or a problem) less severe
Answer:
Convection current
Explanation:
Convection currents occur when a heated fluid expands, becoming less dense, and rises. The fluid then cools and contracts, becoming more dense, and sinks
Hot air rises because when you heat air (or any other gas for that matter), it expands. When the air expands, it becomes less dense than the air around it. The less dense hot air then floats in the more dense cold air, the cold air due to its greater density moves downward, and the cycle continues, this upward and downward movement is called convection current.