What does the children’s experience in a two-dimensional planet tell you about tesser travel?

A two-demensional planet does not support the human form. In chapter five, Meg finds herself feeling crushed and flat. She can’t expand her lungs and her mind won’t work correctly either. She hears the words “Oh, no! We can’t stop here! This is a two-dimensional planet...” and suddenly Meg is thrown through time and space once again where she regains her sense of life. This tells us that tesser travel is not merely for humans or to serve humans.