Process of morphologicaly differentiating male and female sexes is known as

The correct option is sexual dimorphism.

Explanation:
Let us break down the terms and logical reasoning step-by-step to understand why "sexual dimorphism" is the correct answer:

1. Understanding the Terminology:
The term is derived from Greek roots:
- di- meaning "two"
- morphe meaning "form" or "appearance"
Thus, dimorphism literally translates to having two distinct forms. When applied to sexes, "sexual dimorphism" refers to the condition where the males and females of the same biological species exhibit distinct physical or morphological differences beyond the differences in their sexual organs.

2. Morphological Differentiation:
Morphology refers to the size, shape, color, structure, and external appearance of an organism. In many animals, males and females look visibly different. For example:
- In lions, males have a prominent mane whereas females do not.
- In many bird species (like peacocks), males have highly ornate and colorful plumage compared to the duller females.
- In humans, differences in average body size, muscle distribution, and facial hair are examples of sexual dimorphism.
The biological process and occurrence of these differences is called sexual dimorphism.

3. Evaluating the Other Options:
- Polymorphism: This refers to the occurrence of several different forms or types of individuals among the members of a single species, not restricted to just male and female differences (e.g., different castes in ants or bees).
- Variation: This is a very broad term referring to any difference between cells, individual organisms, or groups of organisms of any species caused either by genetic differences or by the effect of environmental factors.
- Therefore, the specific process of morphologically differentiating male and female sexes is uniquely and accurately described as sexual dimorphism.