The answers are:
a. physical geography
b. human geography
Geography is divided into two main branches, physical geography, and human geography, and after that, they branch out much more and include the other geographical disciplines in them.
Physical geography is mainly concerned with the study of the natural characteristics of the Earth, both the ones on the surface and the once close to the surface.
Human geography is mainly focused on the study of the human race, the background, perceptions, interactions, organizing, human groups, effects on and from the environment etc.
Answer:
Earthquakes and volcanoes
Explanation:
Earthquakes are caused by any type of plate movement in response to the plates reacting to one another in some way.
Volcanoes can be caused when there is a plate being sucked under another plate causing magma to rise up and eventually errupt.
These factors contribute to the development of the population.This phenomena had happened in the last 2 centuries in all of the countries to help to improve the conditions of the life.
Because many rivers run swiftly down int mountains.
Hope that helps