A) Another living cell (sry if wrong)
They have contributed to heating up the environment
Answer:
Bird migration is the regular seasonal movement, often north and south along a flyway, between breeding and wintering grounds. Many species of bird migrate. Migration carries high costs in predation and mortality, including from hunting by humans, and is driven primarily by availability of food.
Explanation:
The sympathetic nervous system activates what is often termed the fight or flight response. ... In response to this stimulus, postganglionic neurons principally release noradrenaline (norepinephrine). Prolonged activation can elicit the release of adrenaline from the adrenal medulla.
