The answer is aerobic. Although cellular respiration can happen anaerobically and aerobically, the question states that it requires oxygen. Therefore, it is aerobic.
Answer:
Flatworms and cnidarians
Explanation:
In simple organisms, such as cnidarians and flatworms, every cell in the body is close to the external environment. Their cells are kept moist so that gases diffuse quickly via direct diffusion. Flatworms are small, literally flat worms, which 'breathe' through diffusion across the outer membrane
Answer:
Original Remains Fossil
Explanation:
Fossils that are the actual bodies or body parts of organisms are called original remains fossils. A Mold fossil is a fossil formed when complex parts of an organism are trapped in sediment dissolved away leaving behind a hollow area with the organism's shape. A cast fossil is a fossil formed when sediment fills in the hollow space of the shape of an organism. A carbonized fossil is a fossil when a dead organism is compressed over time and the pressure drives out the liquids and gases leaving behind an outline of the organism