Explanations:The agricultural success of the Indus River Valley is a result of a series of natural events that occurred over time. The sequence of these events is crucial to understanding how the region became ideal for farming. The first event in this sequence is the heavy snowfall in the Himalayas. This snowfall is a critical initial step because it provides the water source that will eventually nourish the valley.
Heavy snowfall in the Himalayas is a seasonal event that occurs during the winter months. The snow accumulates on the mountain peaks and slopes, creating a vast reservoir of water. This snow is essential because it acts as a natural water storage system. When the weather warms up, typically in the spring and summer, the snow begins to melt. The melting snow then flows down the mountains, forming rivers and streams that eventually converge into the Indus River.
The melting snow leads to flooding in the Indus River Valley. These floods are a natural part of the river's cycle and are essential for the agricultural productivity of the region. As the floodwaters recede, they leave behind a layer of silt. Silt is a fine, fertile soil that is rich in nutrients. This silt deposition is what makes the soil in the Indus River Valley so fertile and ideal for farming.
It is important to understand that the heavy snowfall in the Himalayas is the first event in this sequence. Without this initial snowfall, there would be no water source for the subsequent melting and flooding. The melting of the snow and the resulting floods are dependent on the initial snowfall. Therefore, the correct answer is that heavy snows fell in the Himalayas first, setting the stage for the agricultural success of the Indus River Valley.