Microbes
Explainer: Virus variants and strains
When viruses become more infectious or better able to survive the body’s immune system, they become a type of variant known as a strain.
By Janet Raloff
HS-LS4-4
Construct an explanation based on evidence for how natural selection leads to adaptation of populations.
More Stories in HS-LS4-4
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Health & MedicineWill we all need COVID-19 booster shots?
Experts say not yet, but booster vaccines may be coming as new SARS-CoV-2 virus variants keep emerging.
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FossilsScientists Say: Dinosaur
Dinosaurs emerged between 243 and 233 million years ago. While some died out 66 million years ago, others are still with us — birds.
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Health & MedicineSome young adults will volunteer to get COVID-19 for science
Researchers will soon give some healthy people the new coronavirus. Their young volunteers have agreed to get sick to speed coronavirus research.
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ChemistryLet’s learn about acids and bases
Acids give away particles with positive charge. Bases accept positively charged particles. They are both critical for chemical reactions.
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ArchaeologyHarsh Ice Age winters may have helped turn wolves into dogs
In the Ice Age, Arctic hunters may have turned to some game for their fatty bones. Much of those animals’ meat might have been left to domesticate dogs.
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GeneticsScientists Say: Evolution
Evolution is how species change over time. Individuals in the group vary, and some will pass on their genes. Over time, the whole species changes.
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PlantsHere’s how giant pumpkins get so big
Cinderella took a ride in a pumpkin coach. Though real pumpkins do get big enough, here’s why their ride would be uncomfortable at best.
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LifeLet’s learn about alligators and crocodiles
Alligators and crocodiles seem similar — but they live in different places and look different, too.
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AnimalsA single chemical may draw lonely locusts into a hungry swarm
Swarms of locusts can destroy crops. Scientists have discovered a chemical that might make locusts come together in huge hungry swarms.