**Core Concept**
The spherical theory, also known as the "spherical model" or "spherical concept," is a theoretical framework in pharmacokinetics that describes the distribution of a drug within the body. This concept is essential in understanding how a drug is absorbed, distributed, metabolized, and excreted (ADME).

**Why the Correct Answer is Right**
The spherical theory proposes that the body can be represented as a spherical compartment, with the drug being distributed throughout this compartment in a uniform manner. This theory assumes that the drug is evenly distributed throughout the body, with no significant gradients or concentrations. The spherical theory is a simplification of the more complex reality, but it provides a useful framework for understanding the basic principles of drug distribution. The concept is often used in pharmacokinetic modeling and is relevant to the study of drug absorption, distribution, metabolism, and excretion (ADME).

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the spherical theory is not proposed by the "logistic model," which is a mathematical model used to describe population growth and other phenomena.
**Option B:** This option is incorrect because the "one-compartment model" is a pharmacokinetic model that assumes a single compartment for drug distribution, but it is not the same as the spherical theory.
**Option C:** This option is incorrect because the "two-compartment model" is a pharmacokinetic model that assumes two compartments for drug distribution, but it is not the same as the spherical theory.

**Clinical Pearl / High-Yield Fact**
The spherical theory is a simplification of the more complex reality of drug distribution in the body, but it provides a useful framework for understanding the basic principles of pharmacokinetics.

**Correct Answer:** D.