When a seed germinates, which part of the young plant emerges first?

توضیح

The young root breaks out first and grows downwards, anchoring the seedling and taking up the water it needs to keep going, and only after that does growth push upwards into the air. The shoot-first idea comes from assuming light is a seedling's first need, but a seedling under the soil is still living on its own supplies and cannot use light yet.