SSC CGL 2021 PYQ — Question 4

In the following passage, some words have been deleted. Fill in the blanks with the help of the alternatives given. Select the most appropriate option for each blank.
Waterfalls, sometimes called cataracts, arise from an abrupt steepening of a river channel that causes the flow of water to drop vertically, or nearly so. Waterfalls of small (1)______ and lesser steepness are called cascades; the (2)______ is often applied to a series of small falls (3)______ a river. Still gentler reaches of rivers that nonetheless (4)______ turbulent flow and
white water in response to a local (5)______ in channel gradient are rapids.