What are germ layers? What is germ layer homology?

1. Embryonic leaves are such layers of animal embryos, which later turn into different organs and tissues. There are three layers (leaves) in total: endoderm (inner leaf), mesoderm (middle leaf), ectoderm (outer leaf).

Endoderm is responsible for the organs of food, respiration. The ectoderm performs the integumentary and sensitive function of the body. And the mesoderm develops motor and support functions.

2. Homology means that at the beginning of the life of the embryo the germ layers are the same for everyone, and only then, with the further development of the organism, different parts of the body in different organisms develop from the germ layers.