Who would have a use for the ability to make severe weather predictions?
Why would they want this information?
How would they use this information?

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

The reactants are co_{2} aka carbon dioxide and h_{2}o aka water along with light energy