The researcher in the research is most likely studying human-environment interaction and all of its consequences on the locale.
'Climatic variations' and 'Human activities' can be regarded as the two main causes of desertification. removal of the natural vegetation cover（by taking too much fuel wood）, agricultural activities in the vulnerable ecosystems of arid and semi-arid areas, which are thus strained beyond their capacity.
A tributary is a source of water for creeks and is one of the few starts of the water system. It would be d
Answer:
d). It is easier to make a large reflecting telescope than a large refracting telescope.
f). A reflector can collect more light than a refractor.
Explanation:
A telescope is a device that is used to observe distant objects by the use of lenses and mirrors. It is also used to observe different distant objects by their reflection, absorption, emission or the reflection of the electromagnetic radiations.
Most of the professional telescopes are reflectors because :
1. The reflected telescope is able to receive more of the light when it reflects all the light falling on surface. And it is easier for making a large telescope rather then making large lenses for the refracting telescope. So it is easier to make large reflecting telescope than a large refracting telescope.
2. A reflected telescope receives all the wavelength of the light and it reflects all the light falling on the surfaces where it is refracted telescope that contains lenses cannot absorbs all the light and causes the chromatic aberration.
