Human and the Earth

In terms of theevolution of life on Earth,human beings have just arrived.Despite their shoritime on Earth,however,people have brought about enormous changes to the

surface of theplanet一changes far out ofproportion to the interval of time they have occupied it.

People have morecontrol over their surroundings than any other species on Earth.With thecombination of intelligence and manual skill(allowing us to make and use

tools),people havefound ways to use plant and animal resources,mineral ores,fuels,and many othermaterials and resources from the Earth.

As the number ofpeople on Earth increases,it becomes increasingly difficult for the populationto survive on the resources of the land.The amount of land is limited.Although

agriculturalproduction can be increased by use of machinery such as tractors and theaddition of fertilizer,the land ultimately can produce only so much food and nomore.

As the humanpopulation grows,people consume more.Clearly,some locations on Earth alreadyhave too many people;in many of these areas,future increases will surely bring

about more povertyand suffering. Yet people in rich nations use proportionally far more of theavailable resources than people in poorer nations.As they consume these

resources withoutrestraint,they also waste large amounts of them.

People are only avery small fraction of all the living things on the planet.Yet their numberscreate a drain on resources that can't be renewed.For example,the amount ofwater

on Earth islimited,this water is cleaned through natural processes.However,the naturalprocesses for filtering water can clean only a certain amount of water byremoving the

pollution.Likewise,alimited amount of petroleum can be found under the Earth's surface.Petroleum isa valuable resource.Should people use it up to manufacture petrol for

automobiles?Aspeople work to control the planet and make life comfortable,are they using upresources that are needed for their survival?What makes peoplefeel hard to live on Earth?

A.Fertilizer.

B.Lse of machinery.

C.Limited land.

D.Limited mineralresources.