It helps with the optic nerve, if you give me options i can help answer. Sorry if I didnt help :)
The answer is a because if you look at the bone structure in each animal, you would notice how similar they look to one another, and all of the animals above use their legs for the same function which is walking which can suggest that all had a common ancestor.
hopefully this helps
Answer:
Have different numbers of neutrons
Explanation:
Isotopes of an element have different atomic numbers because thy differ in neutron number even though proton number remains the same across the isotopes. The mass number is the summation of the proton and neutron number. Phosphorus has approximately 23 isotopes whose mass number range between 25 and 47. Only ³¹P is stable.