Scientists have discovered how plants manage to live alongside each other in places that are dark and shady. Plants in the deep darkness of a thick forest, where natural supplies are not very great in amount, won’t attempt to top their neighbors in growth as those in moderate (中度的) shade do. In deep shade conditions, it would be a waste of energy and harmful to survival because green shoots would never be able to top their larger neighbors in growth.
So how do plants prevent such growth in deep shade conditions? The secret lies in the clocks inside them, say scientists from the John Innes Centre and the University of Bristol.
They have discovered that when plants notice deep shade, this changes the expression of genes in certain parts of the circadian clock (昼夜节律时钟) — the internal daily time r found in plants and other living things. These clock components perform an additional role in preventing plants from lengthening and over topping neighbors.
The work identifies a previously unknown role of the circadian clock in controlling plant development, and the findings may have possible effects on both natural plant populations and crops. Professor Antony Dodd of the John Innes Centre said, “The biological clock of plants plays a big part in their development and fitness. This work casts new light on a new role of the circadian clock in adapting plants to competition with other plants in their environments.” “It also gives us new insights into how plants adapt to very deep shade, where resources are very limited,” said Professor Kerry Franklin at the University of Bristol.
This work provides evidence for the stability of the circadian clock in stressful environments, and information that may be useful in developing new generations of crops in a challenging climate.
【小题1】What do plants normally do in moderate shade?A.Struggle to preserve energy. | B.Compete for very limited resources. |
C.Try to outgrow their neighbors. | D.Depend on each other to survive. |
A.By changing their gene expression. |
B.By making them realize light change. |
C.By helping them adapt to the darkness. |
D.By controlling their growth in deep shade. |
A.The circadian clock’s role in plant development remains unknown. |
B.Plants’ living environments are very competitive. |
C.The circadian clock affects plants’ adaptability to survival competition. |
D.Plants can adapt to very deep shade where resources are very limited. |
A.To share a new discovery about plants. |
B.To introduce the role of the circadian clock. |
C.To compare plants living in certain conditions. |
D.To explain plants’ secret of living in forests. |
An unwanted TV can feel like a burden to you, especially if it’s an old-style TV set. Yet there are a few ways to dispose of it, depending largely on your TV’s condition. If your TV still works, the best option may be to sell or donate it. If it doesn’t work or if you have difficulty finding someone who wants it, you still have other environmentally friendly options.
Like many electronic products, TVs contain a variety of harmful materials like plastic and heavy metals, which can cause pollution if not dealt with properly. In some US states, TVs are banned from landfills entirely. Even if you face no legal consequences for throwing a TV into the trash, however, there are also practical and ethical (道德的) reasons why recycling is a better decision.
TVs may be recyclable, but that doesn’t mean they can go in your recycling dustbin. It is a good idea to check if your local recycling or waste-management authority accepts e-waste in some form, like special pickup days; just don’t expect it to be quite as easy as putting out your weekly paper and plastic to recycle.
When TVs arrive at a recycling center, they’re often checked to see if they can be repaired and reused, since that’s better than breaking them down for recycling. If not, they’re separated into major components like the screen, plastic and metal frame. The remains of your TV set may go through a shredder (切碎机), with magnets (磁铁) helping remove steel and iron. Other processes can pick out additional metals, including aluminum, gold, silver and tin, while water-separation technology helps divide plastics and glass. Once the components are separated, they can be sold for use in new electronics.
Here is a closer look at how you can find new uses for an old TV that still has life left in it.
【小题1】What does the underlined phrase “dispose of” in paragraph 1 mean?A.Throw away. | B.Deal with. |
C.Pick up. | D.Make up. |
A.Being sentenced to death. | B.Decreasing waste of resources. |
C.Causing serious pollution. | D.Making it easy to handle rubbish. |
A.What parts of TVs can be reused. |
B.How TVs are dealt with at the recycling center. |
C.Why TVs must be recycled in the US. |
D.What difference recycling TVs has from recycling plastic. |
A.The true value of old TVs. |
B.The trouble of getting treasure from TVs. |
C.The new uses of old TVs. |
D.The recycling process of old TVs. |
Mental health is a critical aspect of overall well-being, yet it is often ignored in our fast- paced society.
Studies have shown that a person with good mental health lives longer and has a higher quality of life. The effects of positive mental health on the body are plenty, including reducing the risk of diseases and improving overall physical well-being.
Our mental state has a significant impact on relationships. People with good mental health are more likely to be kind and understanding.
Mental health is as essential as physical health in maintaining a fulfilling life. If we run into trouble, don’t keep it to yourself.
A.Turn to friends or families. |
B.They strongly connect with others. |
C.Physical health has been a problem. |
D.So ways to keep positive must be found. |
E.And a clear mind can help make smart choices. |
F.The mind actually needs as much care as the body. |
G.Mental health is vital for keeping emotional balance. |
Give your dead batteries (电池) a new life. Recycle them!
Batteries are used to power clocks, computers, tools and more. However, your batteries have some serious power when their lives are over.
WHY TO RECYCLE BATTERIES:
Remember, batteries are harmful waste. This means we should properly throw them away. You may not think one little battery can cause that much pollution. But don’t think of it as just one battery—there can be millions. In Canada, each person uses about 20 single-use batteries every year. That’s about 700 million batteries! If all these batteries end up in landfills (垃圾填埋场), the heavy metals inside them can get into the water, land and air. It can be harmful to humans and wildlife.
By recycling single-use batteries instead of throwing them away, you can cut down pollution and also help save energy. All batteries are mainly made of plastic and valuable metals. Through recycling programs, dead batteries can be changed into something useful like steel products, or even new batteries.
HOW TO RECYCLE BETTARIES:
Make a difference by starting to collect batteries at your home or school today. You can prepare a box for battery collection and invite friends, family and classmates to bring in old batteries to be recycled.
There are many ways to deal with your batteries. You can:
● Find a Call to Recycle public collection station near you.
● Ask the store where you bought the batteries if you can return them there.
● Communicate with your local city government to find out if there are special programs for recycling used batteries!
For more information, visit https://ecokids.ca/batteries.
【小题1】“Serious power” in the first paragraph shows that ________.A.batteries are very useful in our life |
B.dead batteries are still valuable |
C.dead batteries can bring bad effects to our life |
D.dead batteries can still provide power |
A.water | B.land |
C.steel products | D.heavy metals |
A.build a public landfill | B.learn more about batteries recycling |
C.sell old batteries to some stores | D.no more buy batteries from stores |
A.young children | B.landfill workers |
C.battery sellers | D.community groups |
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