Ajoint produces movement when its angle decreases which type of movement is it

Does anyone have an answer to this question? if so me.

Does indrect sunlight does not pose any danger to the skin

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