<prompt> true about Giardiasis -Only cyst is infectiveReside in ceacumOnly man to man transmissionExist in one phases  <response>: During unorable conditions in the duodenum enchantment occurs .usually in the colon .Infection of man occurs by ingestion of cyst in contaminated food and water .Infective dose is 10 to 100 cysts refer pgno:31 baveja 3 rd edition 