Today after cutting open a papaya , a plant was found in it:
How is it possible for a plant to grow in a fruit? How does it gets $CO_2$ and light for photosynthesis?
That is a papaya seed showing vivipary, or premature sprouting. The plant is getting all the sugar it needs from the nutrients stored in the seed so it does not photosynthesize. If it were to run out, the plant would die.