Introduction

Topographic maps use contour lines to represent equal elevation.

When you walk across contours:

• Crossing toward inner closed loops means going uphill
• Leaving inner loops means going downhill

In the figure, contour lines are spaced at 25 m intervals.

We track the elevation change as a person moves from point P to point Q and describe the pattern.

🔍 Step-by-Step Interpretation

📌 Start point (P)

P lies near the 550 m contour and is inside a smaller loop, meaning it is on a local high.

📍 Move from P outward

The path crosses toward wider loops →

➡️ Height decreases (Down)
from ~550 → 525 → 500 m

📍 Middle of the path

The path enters another set of contour loops →

➡️ Height increases (Up)
toward another hill (~525–550 m)

📍 Slight drop before final ascent

Between two hills the elevation dips slightly →

➡️ Height decreases (Down)

📍 Final approach to Q

Q is marked near 575 m, above the 550 contour →

➡️ Height increases again (Up)

⭐ Pattern observed

Down → Up → Down → Up

✅ Correct Answer

(b) Down–Up–Down–Up

❌ Why Other Options Are Wrong

(a) Up–Down–Up–Down

Would mean P starts below a peak and repeatedly climbs and falls.

But P begins on a high contour and first movement is downhill → Incorrect start direction

(c) Down–Up–Down

Matches the first three transitions but misses the final climb to Q, which is clearly higher → Incomplete

(d) Up–Down–Up

Again assumes the first movement is upward, which contradicts the map → Incorrect

🎯 Final Conclusion

Following the blue path from P to Q, the elevation:

1. Drops from a hill (P)
2. Climbs toward a second hill
3. Drops into a small saddle
4. Climbs again to reach Q

⭐ Therefore, the correct description is:

(b) Down–Up–Down–Up