Final answer:
The Himalayan Mountains are young, rugged, and still rising due to ongoing tectonic activity, resulting in jagged peaks, while the older Appalachian Mountains have undergone extensive erosion, resulting in smoother and more rolling features.
Step-by-step explanation:
The difference in the appearance of the Himalayan Mountains compared to the Appalachian Mountains can be attributed to their respective ages and the geological processes that have shaped them. The Himalayas are relatively young and were formed by the collision of tectonic plates, which is still ongoing. This has resulted in the rugged, jagged peaks characteristic of young, dynamic mountain ranges. The Himalayas continue to rise each year, and they also experience significant erosion due to water and ice, sculpting sharp features.
In contrast, the Appalachians are much older and have been subjected to hundreds of millions of years of erosion. Formed by ancient collisions of landmasses, including an eventual collision with the supercontinent Gondwana, these mountains have eroded down to their smooth, rolling appearance. This long period of erosion has softened their features, making them less rugged than younger mountain ranges like the Himalayas.