16.
a stream’s discharge (1 point)

decreases between its source and mouth
remains the same throughout its course
is greatest during times of drought
increases between its source and mouth

17.
the suspended load of a stream (1 point)

is deposited before the bed load
consists primarily of highly soluble substances
moves along the bottom of the channel by rolling or sliding
usually consists of fine sand, silt, and clay-sized particles

18.
the most prominent features of a narrow, v-shaped valley, where the stream profile drops rapidly, are 16.
a stream’s discharge (1 point)

decreases between its source and mouth
remains the same throughout its course
is greatest during times of drought
increases between its source and mouth

Q16. The answer is increases between its source and mouth.
A stream's discharge is the amount of water that passes any point at giving time (m³/sec). On the way from the source to the mouth, the amount of water will increase because water is added to the stream from groundwater and tributary streams. That means that more amount of water will pass at the further point from the source suggesting the conclusion that the stream's discharge will increase between its source and mouth.

Q17. The answer is usually consists of fine sand, silt, and clay-sized particles.
A suspended load of a stream is a part of a stream load. The other two parts of the stream load are a bed load and dissolved load. The suspended load consists of particles, usually fine sand, silt, and clay-sized particles, that are carried in the middle part of the stream. However, the size of the particles can depend on the velocity of the stream. That means that stream with higher velocity can carry larger particles.

Q18. The answer is rapids and waterfalls.
V-shaped valleys are deep river valley that at a cross section look like a letter V. They are usually found at the in the upper part of the river. The characteristic of the narrow V-shaped valley is that the stream profile drops rapidly. The common features of this type of V-shaped valley are rapids and waterfalls. The stream profile of the narrow V-shaped valley is the result of cutting the easily eroded bedrock by a stream channel. 

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