A reflex arc is a neural pathway that controls a reflex. In vertebrates, most sensory neurons do not pass directly into the brain, but synapse in the spinal cord. This allows for faster reflex actions to occur by activating spinal motor neurons without the delay of routing signals through the brain.

Lobsters, like snails and spiders, have blue blood due to the presence of hemocyanin, which contains copper. In contrast, vertebrates and many other animals have red blood from iron-rich hemoglobin.

Genes: The DNA is the genetic material. The DNA is made of several nucleotides. A nucleotide means, one nitrogenous base one sugar molecule and a phosphate molecule. These Nucleotides occur in sequences and several nucleotides form one gene ( a functional gene is called a cistron)