Which of the following animals is the most complex? base your decision on body plan, structures used to carry out various functions, and structures used to respond to the environment

flatworms
hydras
sponges
sea urchins

Gregor mendel is best known for his work with pea plants and for uncover many of the mysteries of genetics. one of his major findings stated that there were specific, physical units of inheritance that are transmitted during reproduction. what is the the name given to these units of inheritance which can be found on chromosomes? a) centromeres b) cytoplasm c) genes d) nucleotides