Sperm in the lumen are unable to move independently and require to move through the tubules of the testes.

The correct answer would be smooth muscle contractions.

The testes ducts include seminiferous tubules, rete testis, epididymis, vasa deferens and urethra.

The seminiferous tubules serves as the site of sperm formation. They then migrate to epididymis for storage and maturation.

The sperm then migrate to vasa deferens from epididymis when the penis gets erected.

When sufficient stimulation is achieved, the vasa deferens propels the sperm forward with the help of smooth muscle contractions.

the cell cycle is the final answer! : )

answer:

convection currents in the magma drive plate tectonics. heat generated from the radioactive decay of elements deep in the interior of the earth creates magma (molten rock) in the aesthenosphere. the aesthenosphere (70 ~ 250 km) is part of the mantle, the middle sphere of the earth that extends to 2900 km.