In addition, it is merely a measure self - perceived mate value as opposed to a more objective measure
like bilateral symmetry of the face, level of education, or height.
For animals that lack this
bilateral symmetry — sponges, stinging jellyfish, anemones — the digestive system is more
like a cul - de-sac, a fitting turn of phrase for what is essentially a bag into which food flows, gets digested and then must be expelled before more can be consumed.