Please choose the correct answer to the question: In the initial stages of manned space exploration, scientists needed to address adequate nutrition to provide astronauts with energy throughout the mission. Which of these criteria could not be used when considering food and energy for astronauts during manned space flights?

Answer1: history of space food Answer2: food crumbs in zero gravity Answer3: rehydration of certain foods Answer4: food storage for long periods

Answer format: answer1/answer2/answer3/answer4
Answer: answer1