**Core Concept**
The endodermal cloaca is a critical embryonic structure that eventually gives rise to various parts of the urogenital and gastrointestinal systems. During embryonic development, the cloaca differentiates into the urogenital sinus and the rectum, which are then further modified to form the urinary bladder, urethra, and reproductive organs in males and females.

**Why the Correct Answer is Right**
The correct answer is the structure that does not originate from the endodermal cloaca. The cloaca differentiates into the urogenital sinus, which contributes to the formation of the urinary bladder, urethra, and reproductive organs. In females, the urogenital sinus also forms the upper part of the vagina. In males, the urogenital sinus forms the prostatic urethra and the penile urethra. The rectum, on the other hand, arises from the cloaca but is derived from the ectodermal part, specifically the cloacal membrane.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as the endodermal cloaca gives rise to the urinary bladder, which forms from the urogenital sinus.
**Option B:** This option is incorrect as the endodermal cloaca gives rise to the upper part of the vagina in females, which forms from the urogenital sinus.
**Option C:** This option is incorrect as the endodermal cloaca gives rise to the prostatic urethra and the penile urethra in males, which form from the urogenital sinus.
**Option D:** This option is incorrect as the endodermal cloaca gives rise to the rectum, but it is derived from the ectodermal part, specifically the cloacal membrane.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that the cloaca differentiates into the urogenital sinus and the rectum, with the urogenital sinus giving rise to the urinary bladder, urethra, and reproductive organs in males and females.

**Correct Answer:** D.