Final answer:
The name of the young developing plant inside the seed is called an embryo. This embryo develops from a fertilized zygote and grows to become a new plant, using the seed's stored food reserves until it can photosynthesize.
Step-by-step explanation:
The young developing plant inside the seed is called an embryo. When a seed is formed, it goes through various stages starting from a fertilized egg, also known as a zygote. This zygote divides and gives rise to the embryo, which then develops into a new sporophyte plant. As the embryo grows, it utilizes food reserves stored in the seed until it is ready to begin photosynthesis. The seed also contains a seed coat for protection and may include stored nutrition for the embryo.
The final answer to the question "What is the name of the young developing plant inside the seed?" is: b) embryo.