Choose from the following to label the descriptions. Write the corresponding letters in the correct blank (eg: “A”).
becomes the skin and parts of the nervous system
becomes the blood muscles and bones
becomes the digestive system
not present in diploblastic organisms
The answers are as follows: A, C, B, A, B.
(A) The endoderm is the internal layer that becomes the digestive system.
(B) The mesoderm is the middle layer that forms the blood muscles and bones, and is only present in triploblasts (organisms with three layers of specialized tissue).
(C) The ectoderm is the outermost layer that forms the skin and part of the nervous system.