Which of the following best explains why carbon dioxide must be added to water? a. Carbon dioxide bubbles can’t be produced if it is not added to the solution.

b. Carbon dioxide maintains the green color seen in the plant.

c. Carbon dioxide is a needed reactant (input) of photosynthesis.

d. Carbon dioxide does not need to be added.

The embryos of a bird, a reptile, and a mammal are similar in appearance. how does comparing the physical appearance of embryos of different species support the theory of evolution? a. it shows that these organisms share a common ancestor. b. it provides evidence that these organisms eat the same foods.c. it shows that these organisms share the same habitat.d. it provides evidence that these organisms suffered a genetic mutation.