During mammalian embryogenesis, the first differentiation event that occurs leads to a polarization of the outer cells of the 16-cell morula. This outer layer of cells forms the trophectoderm and the inner, apolar clump of cells become the inner cell mass. The inner cell mass will give rise to:

the entire embryo

Explanation:

The trophectoderm refers to the polarized single cell layer that forms the wall of the blastocyst, thereby forming the first epithelium during embryogenesis. Moreover, the blastocyst is composed of 1-an inner cell mass (ICM) which will form all the tissues of the embryo's body, and 2-an outer layer composed of cells collectively called the trophoblast. The ICM of the blastocyst will form the embryoblast (which subsequently will give rise to the embryo itself) and the fetus, while the trophoblast will form all of the supporting tissues (i.e., amniotic sac, placenta, and umbilical cord). In humans, the blastocyst is the developmental stage of the embryo on day 5 after fertilization.

when a reversible reaction is occurring in both directions at the same rate; the products and reactants do not change in concentration. a chemical reaction where the compound is broken into its constituent parts.