These three layers, the endoderm, the ectoderm and the mesoderm, are called the primary germ layers. After gastrulation, the cup-like embryonic stage that contains at least two distinct germ layers is called the gastrula.n mammals, gastrulation is achieved in a very different way. This is because the outer layer of the mammalian blastocyst, which is roughly equivalent to the blastula, becomes the mammalian placenta and is not available to create the primary germ layers of the embryo.
I think the Wolfram System is the term now used to describe what we currently think of as Mathematica. The term Wolfram Language is the language in which you write code in the Wolfram System, or what we currently call (loosely) the Mathematica language, rather than the whole shebang - FrontEnd, Kernel, etc.. Still, that's just me guessing - I know nothing. :) â cormullion Nov 26 '13 at 20:18.
A function like addition is not only associative, but also commutative, which means that expressions like and with terms in different orders are equal. Once again, the Wolfram Language tries to put all such expressions into a standard form.The standard form it chooses is the one in which all the terms are in a definite order, corresponding roughly to alphabetical order. The Wolfram Language sorts the terms in this sum into a standard order.he associativity of addition means that expressions like, and are all equivalent. But for many purposes it is convenient for all these forms to be reduced to the single standard form. The built â in definitions for Plus are set up to do this.