**Core Concept**
The question pertains to the process of development in the context of embryology, specifically focusing on the correct aspects of development. Development is a complex, highly regulated process involving cellular differentiation, growth, and organization, resulting in the formation of tissues, organs, and eventually, a fully formed organism.

**Why the Correct Answer is Right**
However, since the question does not provide options, I will provide a hypothetical question and explanation.

**Question:** True about development all except:

A. Organogenesis begins after gastrulation.
B. Neurulation occurs after gastrulation.
C. Primary germ layers are formed during gastrulation.
D. Secondary germ layers are formed during organogenesis.

**Why the Correct Answer is Right**
Correctly, organogenesis indeed begins after gastrulation. During gastrulation, the primary germ layers (ectoderm, endoderm, and mesoderm) are formed. Subsequently, these primary germ layers undergo complex processes of cellular differentiation, growth, and organization to form the secondary germ layers, such as the splanchnic mesoderm, parietal mesoderm, and endodermal lining of the gut. Organogenesis then occurs as these secondary germ layers give rise to the various organs and tissues of the body. Neurulation, the process of neural tube formation, occurs after gastrulation as well.

**Why Each Wrong Option is Incorrect**
**Option A:** This statement is incorrect because organogenesis actually begins after the formation of the primary germ layers, during the process of organogenesis itself.

**Option B:** This statement is incorrect because neurulation occurs after gastrulation, but gastrulation is not the only developmental process that occurs after gastrulation; other processes like organogenesis also occur.

**Option C:** This statement is incorrect because the primary germ layers (ectoderm, endoderm, and mesoderm) are indeed formed during gastrulation, not organogenesis.

**Option D:** This statement is incorrect because secondary germ layers are formed during the process of organogenesis, not during gastrulation.

**Clinical Pearl / High-Yield Fact**
Remember the acronym "GAST" to help you recall the sequence of developmental processes: Gastrulation, Acquisition of primary germ layers, Splanchnic mesoderm formation, and finally, Tissue and organ formation.

**Correct Answer:** A. Organogenesis begins after gastrulation.