单选题As a defense against air-pollution damage, many plants and animals _____ a substance to absorb harmful chemicals.A relieveB releaseC dismissD discard

共用题干
Adaptation of Living Things
Certain animals and plants develop characteristics that help them cope with their environ-ment better than others of their kind.This natural biological process is called adaptation.Among the superior characteristics developed through adaptation are those that may help in getting food or shelter,in providing protection,and in producing and protecting the young. That results in the evolution of more and more organisms（生物体）that are better fitted to their environments.
Each living thing is adapted to its way of life in a general way,but each is adapted especially to its own distinct class.A plant,for example,depends upon its roots to fix itseff firmly and to absorb water and inorganic chemicals（无机物）.It depends upon its green leaves for using the sun's energy to make food from inorganic chemicals.These are general adaptations,common to most plants .In addition,there are special adaptations that only certain kinds of plants have.
Many animals have adaptations that help them escape from their enemies.Some are hidden by their body color or shape,and many look like a leaf or a little branch.The coats of deer are colored to mix with the surroundings.Many animals have the ability to remain completely still when an enemy is near.
Organisms have a great variety of ways of adapting. They may adapt in their structure,func- tion,and genetics;in their development and production of the young;and in other respects.An organism may create its own environment, as do warm-blooded mammals（哺乳动物）,which have the ability to adjust body heat exactly to maintain their ideal temperature despite changing weather. Usually adaptations are an advantage,but sometimes an organism is so well adapted to a particular environment that if conditions change,it finds it difficult or impossible to readapt to the new conditions.

The author cites the behavior of warm-blooded mammals in order to illustrate that a living thing may have the ability______.
A: to create an environment of its own
B:to remain still when an enemy is near
C: to make food from its inorganic chemicals
D: to change the color of its skin

共用题干
Adaptation of Living Things
Certain animals and plants develop characteristics that help them cope with their environ-ment better than others of their kind.This natural biological process is called adaptation.Among the superior characteristics developed through adaptation are those that may help in getting food or shelter,in providing protection,and in producing and protecting the young. That results in the evolution of more and more organisms（生物体）that are better fitted to their environments.
Each living thing is adapted to its way of life in a general way,but each is adapted especially to its own distinct class.A plant,for example,depends upon its roots to fix itseff firmly and to absorb water and inorganic chemicals（无机物）.It depends upon its green leaves for using the sun's energy to make food from inorganic chemicals.These are general adaptations,common to most plants .In addition,there are special adaptations that only certain kinds of plants have.
Many animals have adaptations that help them escape from their enemies.Some are hidden by their body color or shape,and many look like a leaf or a little branch.The coats of deer are colored to mix with the surroundings.Many animals have the ability to remain completely still when an enemy is near.
Organisms have a great variety of ways of adapting. They may adapt in their structure,func- tion,and genetics;in their development and production of the young;and in other respects.An organism may create its own environment, as do warm-blooded mammals（哺乳动物）,which have the ability to adjust body heat exactly to maintain their ideal temperature despite changing weather. Usually adaptations are an advantage,but sometimes an organism is so well adapted to a particular environment that if conditions change,it finds it difficult or impossible to readapt to the new conditions.

It can be inferred from this passage that the feathers of a bird are colored______.
A: to frightened its enemies
B: to attract its enemies
C: to adjust its body heat
D: to match its environment

共用题干
Ecosystem
1. The word “ecosystem” is short for ecological（生态的）system. An ecosystem is where living creatures expand within a given area. You can say that an ecosystem is the natural environment where biological organisms（生物）such as plants,animals and humans co-exist in this world. So naturally that includes you and me. Yes,we are all members of an ecosystem!
2 .There are different kinds of ecosystems depending on the type of surface or environ-ment. Most are naturally made such as the ocean or lake and the desert or rainforest.Some are man-made or artificial to encourage co-habitation（同居）between living and non-living things in a monitored environment,such as a zoo or garden.
3 .Plants make up the biggest group of biological creatures within an ecosystem,and that's because they are the natural food producers for everyone. Plants raised in the earth need air and collect sunlight to help them grow. When they grow,the plants and its fruits or flowers eventually become a source of food to animals,microorganisms（微生物）and even hu- mans,of course. Food is then converted to energy for the rest of us to function,and this hap-pens in a never-ending cycle until the living creatures die and break up back in the earth.
4 .Ecosystems are the basis of survival for all living things.We depend on plants and ani-mals for food. In order for us to exist,we need to grow and care about other organisms. We also need to care for the non-living things within our environment like our air and water so we can continue living as a population. Since plants,animals and humans are all of various species（物种）,we all play a role in maintaining the ecosystem.
5 .To preserve our ecosystems,we should stop using too much energy,which happens when we consume more than our share of resources. Humans should not disturb the natural habitat（栖息地）of plants and animals,and allow them to grow healthily for the cycle to con-tinue. Too many people in a habitat can mean displacement（搬迁）: imagine being thrown out of your home because there is no more space for everyone. Worse,overpopulation can also ru- in the environment and cause destruction of existing plants and animals.

Plants,animals and humans are all effective in______.
A: our share of resources
B: a biological creature
C: a given area
D: the maintenance of the ecosystem
E: the source of food
F: various species

共用题干
Adaptation of Living Things
Certain animals and plants develop characteristics that help them cope with their environ-ment better than others of their kind.This natural biological process is called adaptation.Among the superior characteristics developed through adaptation are those that may help in getting food or shelter,in providing protection,and in producing and protecting the young. That results in the evolution of more and more organisms（生物体）that are better fitted to their environments.
Each living thing is adapted to its way of life in a general way,but each is adapted especially to its own distinct class.A plant,for example,depends upon its roots to fix itseff firmly and to absorb water and inorganic chemicals（无机物）.It depends upon its green leaves for using the sun's energy to make food from inorganic chemicals.These are general adaptations,common to most plants .In addition,there are special adaptations that only certain kinds of plants have.
Many animals have adaptations that help them escape from their enemies.Some are hidden by their body color or shape,and many look like a leaf or a little branch.The coats of deer are colored to mix with the surroundings.Many animals have the ability to remain completely still when an enemy is near.
Organisms have a great variety of ways of adapting. They may adapt in their structure,func- tion,and genetics;in their development and production of the young;and in other respects.An organism may create its own environment, as do warm-blooded mammals（哺乳动物）,which have the ability to adjust body heat exactly to maintain their ideal temperature despite changing weather. Usually adaptations are an advantage,but sometimes an organism is so well adapted to a particular environment that if conditions change,it finds it difficult or impossible to readapt to the new conditions.

Some plants and animals develop superior characteristics so that they may______.
A: help others of their kind get food,shelter and other things needed
B: survive even in extremely severe conditions
C: become better adapted to the environments than others of their kind
D: result in the evolution and production of more intelligent organisms

共用题干
Ecosystem

1 The word " ecosystem" is short for ecological（生态的）system. An ecosystem is where living crea-
tures expand within a given area.You can say that an ecosystem is the natural environment where biological
organisms（生物）such as plants,animals and humans co-exist in this world. So naturally that includes you
and mne.Yes,we are all members of an ecosystem!
2 There are different kinds of ecosystems depending on the type of suiface or environment. Most are
naturally made 5uch as the ocean or lake and the desert or rainforest.Some are man-made or artificial to en-
courage co-habitation（共居）between living and non-living things in a monitored environment,such as a
zoo or garden.
3 Plants make up the biggest group of biological creatures within an ecosystem,and that's because
they are the natural food producers for everyone.Plants raised in the earth need air and collect sunlight to
help them grow.When they grow,the plants and their加its or flowers eventually become a source of food to
animals,microorganisms (微生物）and even humans, of course. Food is then converted to energy for the rest
of us to function,and this happens in a never-ending cycle until the living creatures die and break up back
in the earth.
4 Ecosystems are the basis of survival for all living things.We depend on plants and animals for food.
In order for us to exist,we need to grow and care about other organisms.We also need tO care for the non一living
things within our environment like our air and water so we can continue living as a population.Since plants,
animals and humans are all of various species（物种）,we all play a role in maintaining the ecosystem.
5 To preserve our ecosystems,we should stop using too much energy,which happens汕en we consume more
than our share of resources. Humans should not disturb the natural habitat（栖息地）of plants and animals,
and should allow them to grow healthily for the cycle to continue.Too many people in a habitat can mean dis-
placement（搬迁）:imagine being thrown out of your home because there is no more space for everyone.
Worse,overpopulation can also ruin the environment and cause destruction of existing plants and animals.

In an ecosystem,plants,animals and humans live together in________.
A:our share of resourees
B:a biological creature
C:a given area
D:the maintenance of the ecosystem
E:the source of food
F:various species