Where is the illustration
Physical arousal can facilitate passionate love. It is a naturally occurring and deeply embedded trait found within the DNA of living organisms. The purpose of such is the need to propagate the species in order to ensure its survival in the long run of evolution.
Yesshh: flatworms, common worms ("ribbon worms"), clams, snails, octopuses, crustaceans, insects, spiders, brachiopods, sea stars, sea urchins, and vertebrates.
Answer:
Obligate anaerobe an organism that can grow only in the complete absence of molecular oxygen.