Where are you travelling from?
The immigration officer is asking where Suzuki got on the plane. He uses the present continuous form of the verb because the action is still happening: Suzuki hasn't gone through immigration yet, so technically he hasn't arrived yet in Australia.
Have you been to a farm or the countryside during the past few weeks?
The officer is using the present perfect (have+past participle) to ask about recent events or activities. We use "during" to talk about a period of time in which an activity happened/is happening/ will happen.
(This kind of question is asked very often at customs in Australia. To protect Australia's natural environment, customs officials need to stop organic material from other countries being brought into Australia).
Another example is:
What have you been doing during the past few months?
Are you carrying any fresh food, meat or plant-life?
This kind of question is asked very often at customs in Australia. To protect Australia's natural environment, customs officials need to stop organic material from other countries being brought into Australia.
Do you have anything to declare?
The customs officer is asking if Suzuki has anything in his bag, such as duty-free shopping or foods, that he should tell the officials about. The verb "declare" means to tell someone something officially.