Which test is required to diagnose Typhoid?

The chemical test that is used for diagnosis of typhoid is

AIDS is widely diagnosed by

Widal test is used for the diagnosis of which disease?

Which is required for nitrogen fixation ?

Which requires catalyst ?

Which test is conducted to identify HIV ?

Which of the following statements regarding the disease typhoid is/are correct ? (i) Salmonella typhi are the pathogenic bacteria which enter human intestine through contaminated food and water migrate to other organs through blood. (ii) Sustained high fever (39^(@)C " to " 40^(@)C) , weakness, stomach pain, constipation, headache and loss of appetite are some common symptons of typhoid. (iii) Widal test is used for diagnosis of typhoid fever. (iv) The patient of this disease is not required to be treated with antibiotics.