How do host cell proteases contribute to the virulence of the influenza virus?[Fill in the blank]单项选择题
A
a. They degrade viral RNA.
B
b. They cleave hemagglutinin for viral entry.
C
c. They prevent viral replication.
D
d. They enhance immune responses.
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Question textQuestions 25 – 29 Complete this summary of the last two paragraphs of the text by filling in each blank with ONE WORD from the text. Efforts to mitigate 25.Answer 1 Question 13[input] change offer a unique chance to address various environmental issues alongside reducing carbon emissions. However, implementing low-carbon technologies must steer clear of 26.Answer 2 Question 13[input] ecosystems to maximize benefits and avoid unforeseen repercussions. Careful consideration of power plant siting, design, and technology selection is paramount for both financial backers and 27. Answer 3 Question 13[input]. While solar and wind power are widely recognized as 28. Answer 4 Question 13[input] energy options, bioenergy and carbon capture and storage play crucial roles in swiftly reducing emissions in all scenarios. Balancing technology use with 29. Answer 5 Question 13[input] preservation is essential, as revealed by our findings.
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Read the text on renewable energy sources and answer the following questions. There is growing interest and investment in the use of low-carbon technologies to generate electricity. However, all energy production will have environmental side-effects. Our research set out to establish whether renewable energy forms are really better than fossil fuels and nuclear power. In a research paper, we analyzed the environmental impact of electricity generation from renewable sources, nuclear fission power plants and fossil fuels. The environmental impact of any energy source needs to be measured across a range of criteria. We accounted for the environmental effects associated with the production, operation and dismantling of facilities, as well as the production, transport and combustion of fuels. Our study emphatically confirms that fossil fuels – mainly coal – place a heavy burden on the environment and that most renewable power projects have lower pollution-related impacts on ecosystems and human health. Nonetheless, no energy source is without adverse environmental side effects. Photovoltaics (PV) comes out very well in our analysis. Today, the production of PV cells, commonly called solar panels, uses much less energy than previously. The carbon emissions per unit of PV electricity is one-tenth or less of even the most efficient natural gas power plants. However, solar panels require much more space to generate the same amount of power as fossil fuel or nuclear power generators. Also, this need for large tracts of land and can have a negative impact on local species. Does this mean covering huge areas with solar panels is a problem? Not necessarily. The amount of land needed to generate a kilowatt-hour from PV is comparable to that of coal power, when the land associated with mining coal is accounted for. What’s more, about half of the PV installations in our future scenario in 2050 could be placed on rooftops. Environmental effects from hydropower vary widely, we found. Some dams cause significant climate impacts through the emissions of methane from the decomposition of biomass in reservoirs. Other dams cause equally serious ecological problems through habitat destruction. They can also block the migration of aquatic species and reduce sediment flow and nutrient transport, which affects floodplains and deltas. On the other hand, reservoirs form new habitats for birds and other species. Hydropower offers a good example of the importance of site selection and project design. Some projects may be economically viable but ultimately should not be implemented due to the environmental degradation they can cause. For other projects, the impacts can be limited by mitigation strategies such as environmental stream flow and fish ladders, which provide a detour for migrating fish around a hydropower dam. Similar lessons hold for wind power, the first of which is the need to minimise habitat destruction during construction. Then, once facilities are built and up and running, their operations should be adjusted in order to reduce collisions with flying creatures, such as raptors and bats. Also, wind power resources vary widely across locations, which stresses the importance of choosing locations where wind resources are more abundant. Biomass energy, or burning plant material for power, is important in plans to limit global warming. ". When combined with CO₂ capture and storage, it can remove carbon from the air and store it underground, which helps the environment. 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