Important Questions Class 8 Chapter 4 Geography Maharashtra Board

Imp Questions For All Chapters – Geography Class 8

Structure of Ocean Floor

Short Questions

1. What is the average depth of the ocean floor?

• The average depth of the ocean floor is around 3700 metres.

2. What is the continental shelf?

• It is the shallow part of the ocean floor near the coast.

3. Which oceanic landform is most suitable for fishing?

• The continental shelf is most suitable for fishing.

4. Name the deepest trench in the world.

• The Mariana Trench in the Pacific Ocean.

5. What are abyssal plains?

• Abyssal plains are the flat parts of the ocean floor beyond the continental slope.

6. What are marine oozes?

• Marine oozes are deposits formed from fine particles and remains of marine organisms.

7. What is the Chagos Plateau?

• It is a submarine plateau in the Indian Ocean.

8. What is the role of the continental slope?

• It acts as the boundary of continents.

9. Why are volcanic eruptions on the ocean floor dangerous?

• They can cause tsunamis and earthquakes.

10. What is the reference point for measuring sea level in India?

• The sea level at Chennai is used as the reference point in India.

Long Questions

1. Why is the continental shelf important for humans?

• The continental shelf is important for fishing because of abundant marine life, and it contains natural gas and mineral oil.

2. How do marine trenches and deeps differ from each other?

• Marine deeps are shallow and shorter, while trenches are deeper and extend over a longer distance.

3. Why are marine trenches considered geologically active?

• Marine trenches have many active volcanoes and experience frequent earthquakes that can trigger tsunamis.

4. What happens to the land beneath the ocean during low tide?

• During low tide, the level of water goes down, and the land near the coast becomes visible.

5. Why are abyssal plains important?

• Abyssal plains are important because they provide a stable environment for deep-sea organisms and marine deposits.

6. What are marine deposits made of?

• Marine deposits consist of soil, pebbles, volcanic ash, and remains of marine plants and animals.

7. Why are marine oozes significant?

• Marine oozes provide information about the availability of minerals and the type of marine life on the ocean floor.

8. How do earthquakes on the ocean floor cause tsunamis?

• Earthquakes displace large volumes of water, generating powerful tsunamis that can flood coastal areas.

9. Why are marine islands like Iceland and Andaman formed?

• Marine islands are formed when the peaks of submerged hills or mountains rise above the sea level.

10. What is the significance of studying the ocean floor?

• Studying the ocean floor helps in understanding marine life, predicting earthquakes, and exploring resources like oil and gas.