What chemical would build up in the muscles to alert them to a switch from aerobic to anaerobic functioning?

The chemical that would build up in the muscles to alert them to a switch from aerobic to anaerobic functioning is : :Lactic acid
Lactic acid is produced after we worked our heart strenuously, which alert our body to tense up the muscle end slow down any activity that we currently doing to prevent potential organ failure

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.