Carbon dioxide because every other option requires an input.
Answer:
a. A hypothesis that does not generate a testable prediction is not useful.
Explanation:
In the scientific method, we generate a hypothesis to explain a phenomenon. After this, it is necessary to create a method to test the hypothesis and make predictions. Moving forward, we test this methodology, generating results and reject or not reject the hypothesis. If the hypothesis can't be tested, the scientific method can't be applied.
Answer:
Both fish and bird embryos exhibit gill slits and a tail.
Explanation:
According to embryology, all vertebrates exhibit similar traits and structures at their embryonic stage. It becomes very difficult to differentiate between the embryos of a fish, and that of a bird, or embryo of a fish, and a human. These traits, however, disappear, as the case may be, as the embryo develops into an adult. For example, in the case of the embryo of a fish, and a bird, both shows gills slits at their respective embryonic stage. However, the gill slits in fish develop into gills, whereas in the case of birds, it disappears as the embryo develops into an adult.
Diffusion is used. Diffusion is one principle of moving of cells
