Protozoa which produce shells

Explanation

The correct answer is Foraminiferans. Foraminiferans are a group of protozoans that produce shells, often made of calcium carbonate. These shells, also known as tests, are complex and vary greatly in shape and structure. In contrast, Amoebas do not have shells and are characterized by their flexible membranes and movement via pseudopodia. Apicomplexans are primarily known as parasites and do not form shells, while Ciliates use cilia for movement and feeding and also do not produce shells.