What are nonpolar macromolecules found in cell membranes, they preventions from freely entering cells. OA Nucleic acids
OB. Carbohydrates
OC, Proteins
OD. Lipids

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.

It's either -limiting factors or -scarce resources but i'd go with my first answer since the food and water are abundant they really aren't scarce