By the contraction of the spermatic cord, the testis of man are not taken to the abdominal cavity due to this structure

The correct option is: attachment of testis by gubernaculum to the scrotal sac only

Step-by-Step Explanation:

1. Understanding the Anatomy of Testicular Descent:
During embryonic development, the testes develop in the abdominal cavity and later descend into the scrotum. This descent is guided by a fibromuscular cord-like structure known as the gubernaculum.

2. The Anchoring Role of the Gubernaculum:
In adult males, the gubernaculum persists as a short fibrous band that firmly anchors the inferior pole of the testis and epididymis to the bottom of the scrotal sac. This attachment restricts the upward movement of the testes.

3. Opposing the Contraction of the Spermatic Cord:
The spermatic cord contains the cremaster muscle, which contracts in response to cold temperatures or stimulation (the cremasteric reflex), pulling the testes upward towards the inguinal canal. However, the testes are not pulled all the way back into the abdominal cavity because the gubernaculum acts as a physical anchor, securing them firmly within the scrotal sac.