ответenglish7class p.78 ex.5​

1 Virology is often considered as a part of microbiology
2 Viruses can be classified according to the host cell they infect: animal viruses, plant viruses, fungal viruses,and bacteriophages (viruses infecting bacteria, which include the most complex viruses).
3 Another classification uses the geometrical shape of their capsid (often a helix or an icosahedron) or the virus's structure (e.g. presence or absence of a lipidenvelope).
4 A virus is a small infectious agent that can replicate only inside the living cells of organisms.
5 Viruses are found in almost every ecosystem on Earth.
6 Viruses cause a number of diseases in eukaryotes.
7 Viral infections in animals provoke an immune response that usually eliminates the infecting virus.
8 The evolution of viruses, which often occurs in concert with the evolution of their hosts, is studied in the field of viral evolution.
9 While viruses reproduce and evolve, they don't engage in metabolism and depend on a host cell for reproduction.

as for me i like parrots. they are my favourite pets. they are clever and nice. i've got a parrot. his (или сейчас иногда придираются учителя, что, говоря о животных, нужно употреблять it) name is kesha. he's blue. he is little. he has got a small head, a yellow beak, a short neck, two wings and a long tail. he lives in a cage. i like him, because he is very smart (as he can talk) and he is very beautiful.

i think that if a person has a pet, he will be very responsible. 

i prefer having an ordinary pet, because some exotic pets may have different deseases and veterinary surgeon willn't know how to cure these deseases.