Final answer:
The cervix is the portion of the uterus that projects into the vagina. It connects the uterine cavity with the lumen of the vagina and produces mucus secretions that aid in sperm movement.
Step-by-step explanation:
The cervix is the portion of the uterus that projects into the vagina. It is the narrow inferior portion of the uterus that connects the uterine cavity with the lumen of the vagina. The cervix plays a vital role in reproduction by producing mucus secretions that can facilitate sperm movement through the reproductive tract.