Q: When the hemoglobin loses its oxygen, it changes to what color? Read this paragraph and choose the correct option from the provided answers: The structure of heme (Figure 19.29), the iron-containing complex in hemoglobin, is very similar to that in chlorophyll. In hemoglobin, the red heme complex is bonded to a large protein molecule (globin) by the attachment of the protein to the heme ligand. Oxygen molecules are transported by hemoglobin in the blood by being bound to the iron center. When the hemoglobin loses its oxygen, the color changes to a bluish red. Hemoglobin will only transport oxygen if the iron is Fe2+; oxidation of the iron to Fe3+ prevents oxygen transport. Choices: - purple red - grayish red - light pink - bluish red A:
bluish red

Q: What is the term for a galaxy that is a rotating disk of stars and dust? Read this paragraph and choose the correct option from the provided answers: A spiral galaxy is a rotating disk of stars and dust. In the center is a dense bulge of material. Several spiral arms come out from the center. Spiral galaxies have lots of gas and dust and many young stars. The image below ( Figure below ) shows a spiral galaxy from the side. You can see the disk and central bulge. Choices: - cosmic galaxy - nebula - Milky Way - spiral galaxy A:
spiral galaxy

Q: Of course, a net external force is needed to cause any acceleration, just as newton proposed in his second law of what? Read this paragraph and choose the correct option from the provided answers: Of course, a net external force is needed to cause any acceleration, just as Newton proposed in his second law of motion. So a net external force is needed to cause a centripetal acceleration. In Centripetal Force, we will consider the forces involved in circular motion. PhET Explorations: Ladybug Motion 2D Learn about position, velocity and acceleration vectors. Move the ladybug by setting the position, velocity or acceleration, and see how the vectors change. Choose linear, circular or elliptical motion, and record and playback the motion to analyze the behavior. Choices: - land - gravity - speed - motion A:
motion