Answer:
The correct answer is option B, lower than the threshold velocity for sand
Explanation:
Threshold velocity of the soil is the velocity where soil has overcome the gravitational force and the inter particle force and it starts moving. The factors which affect the threshold velocity of soil are –
a) Lower the sand content , higher will be the threshold velocity
b) Size of aggregates in the soil – the larger the size of the aggregate the larger will be its velocity
c) Size of soil particles – soils with soil particle size greater than 1 mm shall move easily.
Considering all the above three factors, it is clear that the threshold velocity of silt is lower than that of sand as the sand content in silt is high and also its particles are finer than that of sand particles.
increased evolution
high population growth
extinction