Final answer:
Sporozoa are generally non-motile and do not have structures for movement like flagella or pseudopodia, but show limited movement during certain life cycle stages through host mechanisms.
Step-by-step explanation:
Sporozoa, a subgroup of protozoa, are distinguished by their lack of movement mechanisms throughout most of their life. Unlike other types of protozoa, sporozoa do not have structures such as flagella or pseudopodia to facilitate their movement. Hence, they are often considered non-motile. However, during certain stages of their life cycle, particularly when the spores are turning into infective forms such as merozoites within their respective hosts, they exhibit very limited movement.
For instance, in the life cycle of Plasmodium, the causative agent of malaria, sporozoites move to the liver after being injected into the host by a mosquito, but they do not use active locomotion like flagellar movement or pseudopods for this. Instead, Plasmodium relies on the host's body movement and fluid dynamics. After invading host cells, they can slightly move and reposition themselves using host cells' structures, yet this is not considered true movement as seen in other protozoan classes.