Arecurrent and more serious form of heartburn, also known as acid reflux, is called

When a virus infects a host cell, it uses the cell's machinery to make copies of its own genetic material in a process called replication. finally, during the process of self-assembly, that protein shell and the copies of the virus's genetic material are assembled into new viruses.

Bc they get tired from playing with other kittens

C- a hypothesis or d- an observation