Positive selection of t cells occur in .the thymus
I think the answer is ice
Answer:
I think that this might be your answer :) I tried hope this helps !
Explanation:
A) Heat exposure Because In terms of weather Heat: Inhaling hot air, induces airway constriction making it difficult to breathe.
Also Of course, it's known that smoke from fire can have a terrible effect on your lungs. It can restrict oxygen flow, which can and most likely be deadly. So the exposure to the heat will distract them cause they cant breath while they work .
The best answer to the question that is being given above would be letter A. The most complex level of organization hierarchy that climate change could potentially affect is Earth's Biosphere - which holds every living thing in the planet. This climate change will destroy it more destruction to Mother Nature occurs.