Questions

Rejuvenation occurs when the river’s base level falls (i.e. when sea level falls). This can be a consequence of either a fall in the amount of sea water or the land rising. Incised meanders are meanders which are particularly well developed and occur when a river’s base level has fallen giving the river a large amount of vertical erosion power, allowing it to down cut. Hence, 2nd statement is correct.

There are two types of incised meanders, entrenched meanders and ingrown meanders.As they are products of rejuvenation, they are not formed in mature stage of a river

Each of the integers in the first set could be combined with any from the second set, giving a total of 4 x 5 = 20 possible pairs.

Of these the combinations that could give a sum of 23 are (5 + 18), and (9 + 14)

This means that the probability of getting a sum of 23 is 2/20 = 1/10