Answer:
sedimentary rocks
Explanation:
can be dated using radioactive carbon, but because carbon decays relatively quickly, this only works for rocks younger than about 50 thousand years. So in order to date most older fossils, scientists look for layers of igneous rock or volcanic ash above and below the fossil.
The answer should be C, It diffuses from the alveoli into the blood.
Alveoli, also called the air sac, is the place where the oxygen we breathed in is exchanged with carbon dioxide that our body produces. Oxygen is passed into the blood in the capillaries through the process of diffusion, while carbon dioxide is diffused from the blood back to the alveoli, so that we can exhale the carbon dioxide after that.
Both a and b are not right because when we breathe in, the oxygen travels from the trachea to the bronchi, to the bronchiole, and to the alveoli, instead of directly into blood vessels like arteries, capillaries, or veins. d is also not right because the direction is wrong.
Therefore, your answer should be C.
The very right of the diagram.
