What is the cause of a muscle spasm

Viruses ) manufacture their own atp, proteins, and nucleic acidsb) use the host cell to copy themselves and make viral proteinsc) use the host cell to copy themselves and then viruses synthesize their own proteinsd) metabolize food and produce their own atp

How do i know when i have a stress headache? what are the symptoms?

Which sti is a common cause of cancer?