What conditions may protozoa cause in humans?

Protozoa are single-celled organisms that can be pathogenic in humans, leading to various diseases. The correct option highlights two significant conditions caused by protozoa: amoebic dysentery and giardiasis.

Amoebic dysentery is primarily caused by the protozoan Entamoeba histolytica, which infects the intestines and can lead to severe diarrhea, abdominal pain, and other gastrointestinal symptoms. Giardiasis, on the other hand, is caused by Giardia lamblia and is characterized by symptoms such as diarrhea, gas, and stomach cramps. Both conditions are directly linked to the ingestion of contaminated water or food, where these protozoa reside.

Understanding the diseases linked to protozoan infections is critical, especially when considering public health measures and sanitation practices to prevent their spread. The other options refer to health conditions that are associated with different etiologies and are not specifically caused by protozoan infections, thus reinforcing the uniqueness of amoebic dysentery and giardiasis as conditions directly attributable to protozoa.