Write the characteristics of animals that possess a notochord throughout their life.

(N/A) Animals that possess a notochord throughout their life are classified under the subphylum Cephalochordata.
Characteristics of Cephalochordata:
- They are exclusively marine animals.
- They are primitive chordates.
- The notochord persists throughout their entire life cycle and extends from the head to the tail region.
- Example: $Branchiostoma$ (also known as Amphioxus or Lancelet).
Note: Urochordata (Tunicata) are also primitive chordates,but in them,the notochord is present only in the larval tail stage and disappears in the adult stage.