Take for example the group of prokaryotes against eukaryotes. They may be similar in a way that they contain cells with organelles such as mitochondria, ribosomes, cytoplasm, and many more. But they may differ in the presence of a cell membrane and a nucleus. Eukaryotes have cell walls and a nucleus, while prokaryotes don't have.
A eukaryotic cell can replicate itself two ways. Hope this helps!
Answer:
The alveolar walls and capillary walls share a membrane. That's how close they're getting. This allows oxygen and carbon dioxide to readily pass from the respiratory system to the circulation. Oxygen molecules bind to red blood cells as they return to the heart.
It is either 1 or 2 but I think it is temp(2)