Clinical features resulting from gastrointestinal anthrax is as
a result of invasion of the following EXCEPT:
A. Gastrointestinal Tract
B. Respiratory system
C. Circulatory svstem

Gastrointestinal anthrax primarily manifests through the ingestion of food contaminated with Bacillus anthracis, leading to symptoms such as nausea, vomiting, fever, and abdominal pain. The bacteria invade the gastrointestinal tract, causing significant inflammation and ulceration.

While the respiratory system and circulatory system can be affected by anthrax, they are part of other forms of anthrax infection, such as inhalational or cutaneous anthrax. Therefore, the primary invasion associated with gastrointestinal anthrax is indeed limited to the gastrointestinal tract itself.