Flat face I believe is your answer
The answer is B. they embody the idea of descent with modification.
Answer:
I would write "terrestrial/lives on land during all life stages" between the frog and pigeon branches.
Explanation:
Jaw evolution has started with fish, so i'd place that before the perch, evolution of four limbs is next and I would plate it between the perch and the frog. Evolution of an egg has ensured that organisms remain terrestrial during all stages of life and don't need to rely on water to lay their eggs. So I would place that between the frog and the pigeon. True mammary glands and true hair, as we know it formed on mammals so i'd place that between the pigeon and the rats (although synapsids evolved similar structures long before birds even existed). And lastly, I would place "walking on two legs" between rats and human branches. Because our ancestors evolved bipedalism relatively late.
It serves to polarization by transmission through a filter. <span>A Polaroid filter is a device used to polarize light. The device filters out one-half of the vibrations of unpolarized light as the light passes through the filter. Unpolarized light enters the Polaroid filter and the polarized light goes out from the filter. The unpolarized light becomes polarized.</span>