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 insulating the body until the accumulation of fat deposits in the wrinkles of the skin, and these often remain until birth.