And I will use the test market to derive a means to make my product an even bigger success.â. To use the test market to improve the productivity of the marketing plan requires a research design that tests variations in the plan. âThere is more to be learned from test marketing than an estimate of trial and repeat.
The mesoderm is one of the three major layers in a developing embryo, referred to as germ cell layers. Other germ cell layers are the endoderm and ectoderm. When the embryo develops, different organs and body parts develop from these germ cell layers.
Epithelial tissues are derived from all of the embryological germ layers: 1  from ectoderm (e.g., the epidermis); 2  from endoderm (e.g., the lining of the gastrointestinal tract); 3  from mesoderm (e.g., the inner linings of body cavities).