For the following histological slide type a list of the structures/cells the arrows are referencing.

During negative selection

Gas exchange in the lungs happens at _____cells.

During positive selection of a T cell

Air in the thoracic cavity can lead to _____.

The____ defense system is  ____.

Leukocytosis

During emphysema surface-area-to-volume ratio ____

Plasma (Effector) cells make

NK cells _____ and _____