The aperture known as the $Ostium$ is present in which part of the female reproductive system?

In the female reproductive system,a tiny finger-like structure which lies at the upper junction of the two labia minora above the urethral opening is called

$X$ - The oviducts,uterus and vagina constitute the female accessory ducts.
$Y$ - The male sex accessory ducts include vasa efferentia,epididymis and vas deferens,while the rete testis is an external genital organ.

Assertion: $Clitoris$ is not a remnant of the $penis$ in females.
Reason: It also has a high blood supply and erectile tissue.

The following is a diagram of a section showing the mammary gland. Identify $P$ and $Q$.

Provide a brief description of the various parts of the female reproductive system.