Use a comma to separate nonessential elements from a sentence. More specifically, when a sentence includes information that is not crucial to the message or intent of the sentence, enclose it in or separate it by commas.
Genital warts are a sexually transmitted infection (STI) caused by certain strains of the human papillomavirus (HPV). These skin growths can cause pain, discomfort, and itching. They are especially dangerous for women because some types of HPV can also cause cancer of the cervix and vulva.
Causes of floaters. Floaters are caused by small pieces of debris that float in the vitreous humour of the eye. They occur behind the lens and in front of the retina. The lens is a small clear structure that focuses light as it enters the eye.