Statement I: Incised meanders are formed in the mature stage of a river.

Statement II: Incised meanders are characterized by rejuvenation and upliftment of land.

Both statements are true, and Statement II correctly explains Statement I.

During the mature stage of a river's cycle, lateral erosion dominates, and the river develops a meandering course over a gentle gradient. If the land experiences tectonic upliftment or the base level falls, the river undergoes rejuvenation.

Rejuvenation restores the river's youthful vigor, increasing its vertical erosive power. As a result, the river cuts downward into the underlying bedrock while preserving its existing meandering pattern. This process transforms normal meanders into deep, steep-sided incised meanders. Therefore, incised meanders are essentially mature stage meanders that have been entrenched due to sudden upliftment and rejuvenation.