(b) : The infective stage of Plasmodium is a minute organism called sporozoite. When the mosquito bites man, sporozoites present in the salivary gland of female Anopheles mosquito are injected into the blood of the man. These sporozoites are spindle-shaped or sickle-shaped uninucleate organisms capable of wrigging (wormlike) movements. Each sporozoite consists of elastic pellicle, cytoplasm and nucleus.