Which type of white blood cell is categorized as an agranular leukocyte?

A. Producing early induced proteins: While natural killer cells can produce cytokines, their primary function is not related to protein production.

B. Promoting opsonization of bacteria cells: Opsonization is primarily performed by antibodies and complement proteins, rather than natural killer cells.

C. Secreting signaling molecules: While natural killer cells do secrete signaling molecules (cytokines) to communicate with other immune cells, their main role is the direct destruction of infected cells.

D. Destroying virally infected cells: The primary function of natural killer cells is to recognize and eliminate virally infected cells and tumor cells, contributing to the innate immune response.

A. Increased surface tension: This would decrease ventilation as it increases the force needed to expand the lungs.

B. Increased lung compliance: Compliance refers to how easily the lungs can expand. Increased compliance makes it easier for the lungs to inflate, thereby increasing ventilation.

C. Fewer alveolar sacs: Having fewer alveolar sacs reduces the surface area for gas exchange, which would likely reduce ventilation efficiency.

D. More airway resistance: Increased airway resistance makes it harder to breathe, so it would reduce ventilation rather than increase it.