The about the size of a walnut and encircles the urethra as it leaves the urinary bladder.
a. testis
b. gonad
c. thyroid gland
d. prostate gland

The answer is, option D. Prostate Gland. The prostate gland is about the size of a walnut, and encircles the urethra as it leaves the urinary bladder. The vital role of a prostate gland is that it secretes fluid necessary in the formation of semen along with the sperms.

What do you mean about innate behavior i don’t get it