Snake venom is chemically classified as a protein. Proteins are large, complex molecules made up of amino acids. Snake venom is a mixture of different proteins, enzymes, and other substances produced by venomous snakes. These proteins play various roles in immobilizing or killing prey, as well as defending the snake from potential threats.

Glycolipids, on the other hand, are a type of lipid (fat) molecule that contains a carbohydrate group. They are not typically found in snake venom.

Polysaccharides are complex carbohydrates made up of multiple sugar units. While carbohydrates may be present in small amounts in snake venom, they are not the primary component.

Steroids are a class of organic compounds, but they are not the main chemical constituents of snake venom. Steroids typically play a role in regulating various physiological processes in animals.

In conclusion, snake venom is primarily composed of proteins, making option 3 the correct answer.