题目选项分析

At approximately 22 weeks, a fetus becomes fully covered by lanugo, or a fine, soft hair that insulates the body until fat deposits accumulate in the wrinkles of the skin, often remaining until birth.

At approximately 22 weeks, a fetus becomes fully covered by lanugo, or fine, soft hair, which insulates the body until an accumulation of fat deposits in the wrinkles of the skin, which often remains until birth.