The correct answer Is true
Macrophages
Using the receptors on their surface and through the facilitation by immunoglobulins that attach to the foreign matter, macrophages 'hold' the foreign bodies in the body and 'ingest' them through phagocytosis. Lysozymes in the cells then in 'digest' the foreign matter.
So, a sudden drop in the death rate means that while everything stays the same, less penguins are dying: the penguins are living longer! This means that the population will increase: there will be more penguins at all times!