Answer:
Being endothermic
Step-by-step explanation:
Humans are not cold-blooded and we don't photosynthesise so only the second option applies to humans;
We produce heat internally within our bodies so we are endotherms, i.e. warm-blooded;
We shiver and have thermogenesis through metabolism to generate heat to keep body temp up and also sweating and physiological mechanisms to cool out bodies down.