This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Protozoa, Subject name: Microbiology
The normal habitat of giardia is- 
Select and explain. 
A. Duodenum and jejunum, B. Stomach, C. Caecum, D. Ileum
A: Duodenum and jejunum
Answer: A: Duodenum and jejunum 
Explanation: Ans. is 'a' i.e., Duodenum and jejunum o Giardia is a flagellate protozoao It is the only common protozoa that inhabits the duodenum and jejunum (upper small intestine) of human.o Infective form - Cysto Mode of transmission - Ingestion of cystMorphologyo G Iambi ia exists in two forms.1) Trophozoite# It is tennis or badminton racket shaped/piriform shaped/tear drop shaped in frontal view and spoon shaped (sickle) in lateral view.# It is bilateral symmetrical and all organs of body are paired with :i) Two nucleic,ii) Four pairs of flagella,iii) Two axostyles,iv) Two parabasal bodies,v) Two sucking discsTrophozoite show "falling-leaf' motility.2) Cyst:# It is oval in shape and contains 4 nuclei, remains of flagella and axostyles.