A scientist examines the embryos of a penguin, a duck, and a bat. She finds that the embryos of penguins and ducks develop in a similar way, whereas the embryos of a bat develop in a way that is different from penguins and ducks. Which statement BEST explains this observation?

Molecules like glucose and amino acids are not lipid soluble, so cannot cross the cell membrane by simple diffusion. instead, they are shuttled across by carrier proteins in the membrane from high to low concentration. does this process require energy from the cell? this is an example of what type of molecular movement?