سؤال قراءة ستيب محلول — الاستنتاج (تدريب 5864)

Some illnesses are caused by bacteria. Bacteria are alive: (1) They’re very small — you can’t see them without a microscope — but they take in nutrients, reproduce and die. Viruses can make copies of themselves only by hijacking the cells of the creatures they infect. When the flu virus is outside of your body – lurking on a doorknob, for instance — it’s dead by any definition. But once inside your body, it shows many of the characteristics of life. Viruses might even be the descendants of living organisms that shed seemingly necessary traits to live more efficiently (with a little help from our cells). (2) ”Most viruses have molecules — genes and proteins —like us and other live beings. However, they need another living being to make these proteins,” says Jordi Paps, an evolutionary biologist at the University of Essex in England. (3) Some researchers point out that many organisms including such parasites as tapeworms that can live in your gut — need hosts to feed them and help them reproduce. Viruses aren’t so different. (4) However, chers say that all organisms, parasites or not, can make proteins by themselves, but viruses can’t, so this is why they do not consider them alive, Paps says. (5) Other scientists see it differently. “Viruses can be regarded similar to ‘seeds’ of plants”, says Gustavo Caetano-Anollés of the University of Illinois. “Some seeds appear dead, and you can keep them for years without anything happening to them until the plant starts growing.”