A wildfire is a fire that bums strongly and out of control on an area of grass or bushes.They often happens in rural areas and without purpose.The fires start from natural causes,like lightning.Humans can start fires with cigarettes or campfires,accidentally.
Sometimes,people can set fires on purpose.This is to help an ecosystem and those that live there.These are controlled burns.The fires help encourage healthy ecosystems and prevent larger,more damaging wildfires.Modem fire experts now know how to set controlled burns that are well planned and safe.
Why is fire necessary?As dead or decaying plants begin to build up on the ground,they may prevent organisms in the soil from getting nutrients.They may keep animals on the land from getting to the soil.This coating of dead matter can also
choke the growth of smaller or new plants.
Whether through natural causes or not,fire removes that layer of decay.The soil gets nutrients from the burned material faster than if it had slowly decayed over time.This allows healthy parts of the ecosystem to thrive.
Some plants actually need fire to continue their life cycles.Seeds from some pine trees grow in pine cones covered in a thick sap(树液).The seeds release from the pine cones when fire melts the sap.Fires allow more seeds to get to the soil and grow.
In an ecosystem,native animals and plants have adapted to survive wildfires.For example,deaths from wildfires are low.They survive by burrowing into the ground or fleeing to safer areas.
Humans are responsible for preventing most uncontrolled wildfires.Nearly 85 percent of wildfires start because of human activity.We have to prevent these damaging fires.Understanding the benefits of fire is the only way to truly keep our ecosystem safe from its dangers.
(1)How does controlled burning affect an ecosystem?
A
A
A.It helps keep wildfires from getting too large.
B.It makes it hard for wild animals to stay alive.
C.It causes large areas of grass to bum strongly.
D.It can create dangerous wildfires in rural areas.
(2)What does the underlined word "choke" in Paragraph 3 mean?
C
C
A.Help.
B.Experience.
C.Limit.
D.Fuel.
(3)Why do pine trees need fire to reproduce?
B
B
A.The fire help the pine trees' seeds grow fast.
B.The seeds can get out when fires melt the sap.
C.The fire keeps birds away from pine trees' seeds.
D.The fire provides a source of nutrients for the seeds.
(4)What can be the best title for this text?
D
D
A.The Causes of Wildfires .
B.An Healthy Ecosystem.
C.Fire Helps Plant Reproduction.
D.The Ecological Benefits of Fire.