Final answer:
The term for very fine, soft, downy hair is lanugo, which covers the fetus's face and body in the womb and is shed before birth.
Step-by-step explanation:
The term for very fine, soft, downy hair is lanugo. This type of hair is typically found on a fetus inside the womb. Lanugo is fine and colorless, and it covers the fetus's face and body until it is shed close to the time of birth.
It is part of the natural development process and helps to keep the fetus warm. In the context of birds, another example of fine, downy material is the down feathers, which are not the same as lanugo but also serve as insulation for the birds. While lanugo is found in humans, down feathers are found in birds, and they provide excellent insulation, trapping air in spaces between the loose barbules.