The skin is an important organ in the body of humans and it helps in covering the whole body. It helps in protecting the body from injuries and also help in the regulation of the temperature if the body.
The skin protect the body against illness by producing sweat and oil and also the skin acts as a barrier.
'He had left the house' can function on its own as a sentence. That's the independent clause. 'before mother arrived' cannot function on its own. it is a sentence fragment, or a dependent clause
