Answer: false
Explanation: it means they run together
They believed this because the continents appear to have once been fitted together and it was called pangaea
According to the endosymbiotic theory of the origin of both chloroplasts and mitochondria, the ancestors of these two organelles were free-living prokaryotic cells. This theory states that an early eukaryotic cell engulfed a prokaryotic cell by endocytosis, much as one of our phagocytic white blood cells engulfs a bacterium.
A - The alveoli have a membrane that is only one cell thick to allow for a short diffusion time to capillaries.