Differentiate between:

a. Open and closed circulatory system

b. Oviparity and viviparity

c. Direct and indirect development

d. Acoelomate and pseudocoelomate

e. Notochord and nerve cord

f. Polyp and medusa

a. Open and closed circulatory system

b. Oviparity and viviparity

c. Direct and indirect development

d. Aceolomate and pseudocoelomate

e. Notochord and nerve cord

f. Polyp and medusa