Worldwide, the United States is one of the biggest greenhouse gas emitters. The Obama administration began efforts to drop those numbers by increasing vehicle fuel economy standards in 2011 and with its Clean Power Plan proposals in 2015.

No one can travel inside the earth to study what happens there. So scientists must do their best to replicate real-world conditions inside the lab.

Bone marrow contains hematopoetic stem cells, the precursors to every blood cell type. These cells spring into action following bone marrow transplants, bone marrow injury and during systemic infection, creating new blood cells, including immune cells, in a process known as hematopoiesis.