Praxis II Middle School Content Knowledge Test Prep

Answer: E, Distinguishing features of viruses include all of the listed choices above. Viruses are found in virtually every ecosystem on the planet, and over 5,000 different types of virus have been described in detail.

Key Takeaway: Because viruses do not possess cells and do not have the ability to replicate on their own, their status as living organisms is hotly debated. Viruses have been known to infect all types of organisms. Viruses do have a defined life cycle consisting of attachment to the cell, penetration inside the cell, replication and assembly using the cell’s machinery, and release of the virus from the host cell, which usually results in death of the host. Viruses are spread through a host of methods in humans, including through virus-carrying organisms (vectors), person-to-person contact, sneezing, and sexual contact.