What is required before using a respirator?

Which is an effective way to prevent bullying and harassment

At school, there have been a lot of rumors going around about how certain sexually transmitted diseases are spread. which skill would be most valuable to you take the necessary steps to learn what you need to know to protect yourself? a. self-direction b. critical thinking c. problem solving d. effective communication       select the best answer from the choices provided.

Viruses use the host's machinery to make copies of themselves. however, some human viruses require a type of replication that humans do not normally have. for example, humans normally do not have the ability to convert rna into dna. how can these types of viruses infect humans, when human cells cannot perform a particular role that the virus requires? a) the virus causes mutations in the human cells, resulting in the formation of new enzymes that are capable of performing these roles.b) the viral genome codes for specialized enzymes not in the host.c) the virus infects only those cells and species that can perform all the replication roles necessary.d) viruses can stay in a quiescent state until the host cell evolves this ability.