It might be said that karst and hydrothermal features are the ...

[Chloeellawright]

It might be said that karst and hydrothermal features are the result of underground fluvial processes and are covered in the Karst and Hydrothermal chapter of your textbook while surface fluvial processes form the core of the Fluvial Processes chapter. Compare and contrast the actions of water as a landscape formed underground and at the surface.
 
  What will be an ideal response?

Question 2

Why don't hot springs erupt at regular intervals?
 
  What will be an ideal response?

[AngeliqueG]

Answer to Question 1

Answer: Water is in much different circumstances underground as opposed to above ground: 1) channelization above ground, 2) much dissolved minerals below ground, 3) little hydraulic force underground, etc.

Answer to Question 2

Answer: Regular eruptions are so very rare. The eruptions are predicated on the presence of enough superheated water present. After an eruption, this water takes time to build up and timing depends on the amount of water that must be replaced and the availability of that water in the plumbing system. Droughts and earthquakes can disrupt the plumbing away from regularity.