Which is the primary sex organ in males?

Why are the testes in human beings and mammals situated outside the abdominal cavity within a pouch called the scrotum?

Which one of these is not an accessory gland in the male reproductive system?

Which duct is formed by the union of the vasa efferentia and the seminiferous tubules?

In which of the following animals do the testes descend into the scrotum only during the breeding season?

$A$ pair of bulbourethral glands, also called $...A...$ glands, are present on either side of the $...B...$. They secrete $...C...$ fluid and $...D...$ for lubricating the penis. Here $A, B, C$, and $D$ are: