How is outer surface of skin made waterproof and oily?

Explanation

To understand how the outer surface of the skin is made waterproof and oily, we can break it down into the following steps:

### Step-by-Step Solution:

1. **Understanding Skin Structure**: The skin is the largest organ of the body and consists of multiple layers. The outermost layer is called the epidermis, which plays a crucial role in protection and moisture retention.

2. **Types of Glands in the Skin**: There are two main types of glands in the skin that contribute to its waterproof and oily characteristics: sweat glands and sebaceous glands.

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