Amniotes produce eggs that contain fluids that bathe the embryo during?

The answer is gestation

Amniotes are those animals that have the ability to lay eggs on land. The egg contains the embryo which is bathed with nutritive substance that is watery in nature.

Explanation:

This fluid is the amniotic fluid which protects the embryo from any physical damage and also provides nutrition.

It ensures to prevent desiccation or dehydration of the developing embryo. During the rupture of the egg, the amniotic fluid is released and is no longer the part of the foetus.