When the main rivers flow parallel to each other, and the tributaries join them at right angles, such a pattern is called a _______ drainage pattern.

Correct option is A

• A trellis drainage pattern forms when the main rivers flow parallel to each other, usually along valleys formed by folded or tilted rock layers, and the tributaries join them at nearly right angles.
• This type of drainage pattern is common in regions with alternating hard and soft rock strata, where differential erosion occurs.

Information Booster

• Trellis patterns are indicative of regions with folded topography, such as areas affected by tectonic activity.
• Examples of such patterns can be found in the Appalachian Mountains of the USA.

Other drainage patterns include:

• • Centripetal: Streams converge towards a central point, like in a depression or basin.
  • Radial: Streams flow outward from a central high point, like a volcanic cone.
  • Dendritic: Streams branch out in a tree-like manner, forming in areas of uniform rock resistance.