What are the rungs of the dna ladder made of?

According to the cladogram, which organisms have roundworms as a common ancestor?

Which of the following shows the correct order in which light information travels through the eye? (2 points) lens, pupil, retina, optic nerve pupil, lens, retina, optic nerve pupil, lens, optic nerve, retina lens, pupil, optic nerve, retina

Does anyone know what a poms statement is for biology? i don't know what it is and i have an assignment on it tomorrow, will award the best answer a brainliest!