🔍 Key Concepts

• Diurnal variation of pressure is the regular daily rise and fall of atmospheric pressure, especially noticeable in the tropics • In low latitudes (tropics), this daily pressure change is relatively regular and can be a few millibars between the highest and lowest values • Think about what would be a realistic daily pressure swing in fair‑weather tropical conditions, not storm situations

💭 Think About

• Compare each choice to what you know is a typical daily pressure pattern in the tropics: would such a small or such a large change realistically go unnoticed or be considered extreme on a barometer? • Eliminate values that would be too small to be significant as a known phenomenon, and too large to occur routinely every calm day • Remember this is normal diurnal variation, not pressure changes caused by passing fronts or hurricanes

✅ Before You Answer

• Make sure you are thinking of normal fair‑weather daily cycles, not weather‑system pressure changes • Ask yourself which value is large enough to be clearly measured and charted every day, but not so large that it would suggest a major weather disturbance • Verify that the value you choose seems reasonable as a routine daily range seen in low latitudes on a barograph record