What did Lewis and Clark each do for a living before the expedition?

Lewis knew that exploring the Louisiana Territory would be no small task and began preparations immediately. He studied medicine, botany, astronomy and zoology and scrutinized existing maps and journals of the region. He also asked his friend Clark to co-command the expedition. I hope this is helpful :)

begins a massive airlift of food, water, and medicine to the citizens of the besieged city

is this a multiple choice question? if so, could i see the answers to give you the right one!