SORU: aşağıdaki parçaya göre cevaplayınız
It's implied in the passage that ........... .
The scientists are trying to find the doorway to another world which they believe was found in the 1930s by a man who escaped from one of the communist prison camps. They set off from the warmth of St Petersburg by plane and end up walking along the freezing valley of a river running out of Lake Neranda. They are searching for a mysterious waterfall that never freezes , behind which they will find the doorway. There are eight of them and they walk in pairs; each pair with their sled of supplies pulled by dogs.