The correct option is 1 and 3 only.
Explanation
Geomorphic processes are broadly classified into endogenic (internal) and exogenic (external) forces. These two opposing forces continuously interact to shape the Earth's surface. Endogenic forces generally create relief features, while exogenic forces work to level them down through gradation.
Statement-wise Analysis:
- Statement 1 is Correct: Endogenic forces originate from within the Earth (e.g., volcanism, diastrophism). They are primarily responsible for creating vertical irregularities, such as mountains, plateaus, and plains. Therefore, they are termed land building forces.
- Statement 2 is Incorrect: Exogenic processes derive their energy mainly from the sun and atmospheric gradients. Their primary action involves weathering, mass wasting, erosion, and deposition. While deposition creates landforms, the overall nature of exogenic processes is denudation or land wearing, not land building.
- Statement 3 is Correct: The ultimate goal of exogenic processes is gradation-the leveling of the land. Through degradation (erosion of highlands) and aggradation (filling of lowlands), these processes tend to remove relief variations, theoretically aiming to reduce the land surface to a base level (peneplain).
Key Takeaway:
Endogenic forces are constructive (creating relief), whereas exogenic processes are destructive or gradational (leveling relief).