. which of the following correctly identify which organs develop from different embryonic tissue layers in a frog? liver develops from endoderm, nerves develops from mesoderm, muscles develop from ectoderm brain develops from endoderm, heart develops from mesoderm, epidermis develops from ectoderm liver develops from endoderm, heart develops from mesoderm, brain develops from ectoderm notochord develops from endoderm, liver develops from mesoderm, eye lens develops from ectoderm