Question

venus had a runaway greenhouse effect, but earth does not because
venus retrograde rotation caused the carbon cycle to reverse.
venus has a very transparent atmosphere which allows more of the suns light to reach the ground.
venus has more carbon dioxide in its atmosphere.
venus resurfacing events released tremendous amounts of heat from the interior of the planet.

Explanation:

The runaway greenhouse effect on Venus is mainly due to its thick atmosphere rich in carbon - dioxide. Carbon dioxide is a potent greenhouse gas that traps heat. Earth has a much lower concentration of carbon dioxide in its atmosphere. Venus' retrograde rotation has no direct link to the carbon - cycle reversal causing the greenhouse effect. Venus has a thick, not transparent, atmosphere. Resurfacing events releasing heat are not the main cause of the greenhouse effect.

Answer:

Venus has more carbon dioxide in its atmosphere.